Birds in an urban garden of Venezuela

ANARTIA

Publicación del Museo de Biología de la Universidad del Zulia

ISSN 1315-642X (impresa) / ISSN 2665-0347 (digital)

Anartia, 31 (diciembre 2020): 63-77

Birds at a feeder in an urban garden in Venezuela:

abundances, interactions and fruit preferences

Pájaros en un comedero de un jardín urbano en Venezuela: abundancias,

interacciones y preferencias de frutas

Andrés E. Seijas

& Sara F. Seijas-Falkenhagen

Universidad Nacional de los Llanos Occidentales “Ezequiel Zamora” (UNELLEZ), Guanare, Portuguesa, Venezuela.

aeseijas@gmail.com

Gaspar de Orense 828, Quinta Normal, Santiago, Chile. sarafseijas@gmail.com

Correspondence: A. E. Seijas: aeseijas@gmail.com

(Received: 08-10-2020 / Accepted: 12-12-2020 / On line: 26-02-2021)

ABSTRACT

From December 2019 to May 2020 the birds visiting a feeder with fruits were recorded. Six trials were performed, varying

the location of the feeder (at open sky or under a tree canopy) or the two pieces of fruits oered (selected among banana,

plantain, papaya or mango), which were placed in contact in the center of the feeder or separated toward its corners. e

video recordings were watched to identify and quantify the number of species and individuals visiting the feeder and their

fruit preferences. e hierarchies and the degree of exclusivity (monopoly) in the use of the feeder (%Exc) were analyzed

to determine their relationships with the weight of the birds. e eects of the placing of the fruit pieces and of the feeder

itself on the frequency of visits were also analyzed. Sixteen species went down to the feeder for a total of 2493 visits. e

Blue-gray Tanager, the Pale-breasted rush, and the Tropical Mockingbird jointly represented 66% of the total time spent

at the feeder, whereas eight species together represented less than 10% of that time. e frequency of visits (v/h) and the

time spent at the feeder per recording hour (min/h) varied widely among trails. ere was a positive correlation of the

hierarchies and the %Exc with the weight of the birds (n=12; r

= 0.745, P =0.005, y r

= 0.731, P =0.007, respectively).

e v/h increased when the pieces of fruits were located separated in the feeder but were not aected by the position of the

feeder. When two types of fruits were oered simultaneously to the birds, always three or more species showed preference

for one of them. e frequency of visits and the time spent at the feeder by each species varied widely depending on the

fruit oered and hierarchical interrelations among the birds.

Keywords: feeder, feeding preferences, interspecic interactions, Neotropics, urban birds.

RESUMEN

Desde diciembre 2019 a mayo 2020 se grabaron en video las aves visitantes a un comedero provisto con dos trozos de fruta

(seleccionadas entre banana, plátano, papaya o mango). Se realizaron seis pruebas en las que se varió la ubicación del come-

dero (a sol abierto o debajo de la copa de un árbol) y la disposición de dos trozos de fruta o (juntos o separados). Las graba-

ciones se revisaron para identicar y cuanticar las especies e individuos visitantes, la frecuencia y duración de las visitas y

las preferencias por fruta ofrecida. Se analizó la correlación entre las jerarquías de las especies y la exclusividad (monopolio)

en el uso del comedero (%Exc) con el peso de las especies, así como la relación entre la tasa de visitas por hora (v/h) y la

ubicación de las frutas y del comedero. Dieciséis especies bajaron al comedero con un total de 2.493 visitas. El Azulejo, la

Paraulata Montañera y la Paraulata Llanera en conjunto representaron 66% del tiempo de ocupación del comedero (minu-

tos por hora de grabación, m/h) mientras que ocho especies en conjunto representaron menos del 10% de dicho tiempo.

A. E. Seijas & S. F. Seijas-Falkenhagen

Las v/h y el tiempo de permanencia (min/h) de cada especie variaron ampliamente en las distintas pruebas. La posición

jerárquica de las especies y el %Exc correlacionaron positivamente con el peso de las aves (n=12; r

= 0.745, P =0.005, y r

= 0.731, P =0.007, respectivamente). Las v/h incrementaron cuando los trozos de frutas se encontraban separados en el

comedero pero no se vieron afectadas por la ubicación del comedero. Cuando se ofreció a las aves simultáneamente trozos

de dos frutas distintas, siempre tres o más especies comieron preferentemente de una de ellas. La frecuencia de visitas y

tiempo de uso del comedero por cada especie fue muy variable, dependiendo principalmente de las frutas ofrecidas y de las

interacciones jerárquicas entre las aves.

Palabras clave: Aves urbanas, comederos, interacciones interespecícas, Neotrópico, preferencias alimentarias.

worth millions of dollars (Chace & Walsh 2004, Ishigame

& Baxter 2007). It has generated a vast scientic literature

and has extension and teaching programs in public institu-

tions and universities (Audubon, n/d, omas et al. 1973,

Cecil 2002, Gowen 2004, Adams 2005).

Articial feeding of birds (and other wild animals)

could have signicant ecological eects (See review in

Dunkley & Cattet 2003) and not all of them benecial

from a conservation point of view. e quantity and qual-

ity of food oered in articial feeders can have negative

consequences, such as the transmission of diseases be-

tween the species that visit it, facilitate the proliferation

of unwanted species, malnutrition of the diners due to the

supply of inappropriate food, among other undesirable af-

fects (Tablado-Almeda 2006, Ishigame & Baxter 2007,

Orros et al. 2015, Galbraith et al. 2017), so its potential

implementation for conservation should be based on well-

conducted investigations (Fuller et al. 2008).

In Latin America, studies on urban ecology are scarce

(Leveau & Leveau 2004, Bellocq et al. 2017), and even

less are those dedicated to birds that use articial feeders

(Echeverría & Vasallo 2008). In the case of Venezuela,

the installation of bird feeders has been recommended

for people’s enjoyment and to provide opportunities to

learn about birds interspecic hierarchies when compet-

ing for food (Phelps 1999, Caula & Manara 2015). e

preferences of some bird species for dierent types of food

were succinctly described by Aveledo (1968). ese later

readings oer general recommendations on how to x the

feeders (location, design, and type of food) but no data

are provided to support the options they mention. Levin et

al. (2000), Sainz-Borgo & Levin (2012) and Sainz-Borgo

(2017) conducted more detailed studies on the interac-

tions of birds in feeders established in Caracas, but the em-

phasis of these investigations was to determine the validity

of some ecological or behavioral theories.

In this article we describe the characteristics of the as-

semblage of birds visiting an articial feeder with fruit in

the garden of a house located on the periphery of Guanare

(Portuguesa, Venezuela). e dynamics of this assemblage

INTRODUCTION

e concentration of human population in towns and

cities is a phenomenon that continues to grow worldwide

(Grimm et al. 2008, Faeth et al. 2011, Sanz & Caula 2014,

UN 2019). e occupation and adaptation of spaces for

the settlement of people bring about drastic change in the

characteristics of the aected lands, which makes them,

to a greater or lesser extent, uninhabitable for most of the

species of living organisms that occupied the unaltered

environment or, on the contrary, creates favorable condi-

tions for species adaptable to the new environment (Chace

& Walsh 2004, Tablado-Almeda 2006). e further the

urbanization process progresses, the fewer possibilities of

direct contacts between people and the native fauna and

ora of the region occupied (Gaston et al. 2007). Parks

and dierent green areas of cities serve to attract or main-

tain a fraction (generally very small) of animals and plants

displaced by the anthropization process (Marzlu 2005;

Evans et al. 2009). House gardens also fulll this func-

tion (Gaston et al. 2005, Fuller et al. 2008, Akinnifesi et

al. 2009, Goddard et al. 2009, Seijas & Seijas-Falkenhagen

2020), although with a much lower eectiveness due to

their small sizes.

People living in cities have little opportunity to observe

“wild” animals other than those capable of occupying the

green areas and gardens mentioned in the previous para-

graph (Miller 2005, Goddard et al. 2009, Tryjanowski

et al. 2015). One way to increase the possibilities of ob-

serving these animals in their homes is by providing them

with shelter or nesting structures, as well as water and food

that serve as attractants (Hostetler et al. 2003, Burton &

Doblar 2004). e adaptation of gardens with some of the

mentioned attractions is an activity in which millions of

people participate, particularly in developed countries in

temperate zones (Fuller et al. 2008, Warren et al. 2010)

and, perhaps, also in countries in tropical regions for which,

in any case, there are very few published studies. Arranging

backyards and gardens to attract wildlife species (particu-

larly birds) is an activity that supports an entire industry

Birds in an urban garden of Venezuela

and the interactions among species are analyzed, as well

as the preferences for some fruits and the inuence that

some simple elements of the feeder design, such as its loca-

tion or disposition of fruit pieces oered can exert on the

frequency of visit or consumption of fruits by the dierent

bird species. Based on the results, some basic management

recommendations are presented.

MATERIALS AND METHODS

e study took place in a garden of 500 m

located in a

house of La Colonia neighborhood, outskirts of Guanare,

Portuguesa state, Venezuela. Details on the characteristics

of this garden are found in Seijas & Seijas-Falkenhagen

(2020). Birds have been fed daily with fruits in this garden

since 2003. For this study, the feeder consisted of a square

concrete block (40cm × 40cm and 5cm thick) placed at

ground level. e pieces of fruit were placed on the sur-

face of this block, and covered with a grid (5×5) of plastic-

coated wires. e grid impeded the birds from taking out

or turning upside down the food, but also served for the

birds as a perching device (Fig. 1).

Two feeders were prepared, one at the open sky, on the

oor of the house’s parking space and the other under the

canopy of a Pomagás tree (Syzygium sp). is last feeder

was placed on the ground, 0.55 m from the trunk of the

tree and 2.40 m from the edge of its canopy. e beginning

of the canopy was 1.9 m above the feeder. Only cultivated

fruits were oered to the birds (banana, plantain, papaya

and mango) not to attract some abundant granivorous

birds common in the city (mostly dierent pigeon species;

Seijas et al. 2011) and because frugivores seem to be more

aected by the eects of urbanization than omnivores and

granivores (Sanz & Caula 2014).

e activities of the birds at the feeder were recorded

on video with a cell phone placed on a tripod at a height

of 30 cm and 1 m away from the feeder. e recordings

were grouped into trials (or treatments) (Table 1). Each

trial consisted of oering the birds two pieces of 150g of

the same fruit or dierent fruits, which were placed on al-

ternate days either together (in contact) in the center of

the feeder, or separate (at least 20 cm apart) towards the

le or right corners of it (from the recording perspective).

In any case, it was considered that the food was supplied

ad libitum, since the birds never completely consumed it

in the total period of around one hour from the beginning

of the rst recording session to the end of the last one.

e recording sessions of the rst four trials were car-

ried out exclusively on weekends, to minimize human dis-

turbances typical of working days in the mornings. In the

last two treatments, the recordings were made on consecu-

tive days since they coincided with the connement forced

by the quarantine due to the coronavirus pandemic.

e position of each piece of fruit (le or right) was

alternated every day, to detect and correct possible biases

due to the location of the food (Levey 1987, Jackson et

Figure 1. View of the feeder and the recording device. A plastic ladder protects the cell phone from the sun and rain and prevents birds

from perching on it and knocking it down.

A. E. Seijas & S. F. Seijas-Falkenhagen

al. 1998, Bosque & Calchi 2003). In the fourth and h

trials (Plantain-banana and Mango-banana, respectively)

the pieces of fruit were always separated, with the banana

always on the right. In these cases, what changed was the

location of the feeder, which was alternately one day at

open sky and the other under the Pomagás tree.

For the rst four trials, four videos of approximately

seven minutes each were recorded every sampling day. e

rst one started 10 minutes before sunrise, the second one

at sunrise and the other two sessions at 20 and 40 min af-

ter sunrise, respectively. Due to diculties of visibility and

the low number of birds visiting the feeder very early in the

morning, in the last two trials, the number of recording ses-

sions was reduced to just three daily, but with an increased

duration of about 10 minutes each, with a separation of 15

minutes between them, the rst one beginning at sunrise.

e videos were then transferred to a computer for their

analyses. e eective recording time was taken as the gross

recording time minus 30 seconds, considering that the be-

havior of the birds in the rst 15 and last 15 seconds of each

session may be conditioned by the presence of the research-

er placing and removing the recording device.

Each bird that came to the feeder was registered as a

visit. A bird was considered to be using the feeder when

perched on it (even if not eating) or when eating (even if

not perched on it), which occurred occasionally in the case

of larger birds. e following information was taken for

each visit: species, arrival time, interaction with other birds

in the feeder (share with or expel the preceding occupant),

number of times the bird pecked each of the pieces of fruit

supplied, time and causes for leaving the feeder (displaced

by another bird, in pursuit of another bird, approach of

the investigator, or for unknown reasons). For each trail

we calculated the visitation rate of every bird species as the

total number of visits per eective recording hour (v/h)

and the cumulative time at the feeder (total time spend in

minutes per eective recording hour; min/h).

For each visiting bird, the time spent eating from a

piece of fruit (right or le) was calculated prorating the

total time at the feeder according to the number of pecks

on each piece. Indirect data on the reproductive activity of

a species were taken by noting if the visitor was a juvenile

and, in the case of adults, if they carried food in their bills

when leaving the feeder. Using Microso Excel ©, the resi-

dence time and time shared in the feeder was calculated

for each visitor, both with the eight individuals that pre-

ceded it and the eight that arrived aer it.

e interactions between birds can be very complex

(Senar et al. 1989, Hurd & Enquist 2001, Rose & Soole

2020), but for the purposes of the study only two pos-

sibilities were considered: 1. Displacement, when a bird

evicts or expels another completely out of the feeder, and

2. Sharing, when the bird or birds remain for a time to-

gether in the feeder, even when there may be threats, ght-

ing postures and even attacks between them, but which do

not end (at least for a time) with the abandonment of the

feeder from any of the contenders. In the rst case, when

individuals display ghting postures and threats between

them, the one that retreats from the feeder was considered

the loser and the one that remains the winner (Wojczu-

lanis-Jakubas et al. 2015); however, interactions are not

always one-to-one. Sometimes two or more individuals at

the feeder were simultaneously displaced by a bird arriving

suddenly or ying low towards them. In these cases, the

newcomer was considered the winner and all those that

leave the feeder as losers. We expected to nd a hierarchy

of dominance between species in relation to body weight,

where larger species dominate over the smaller ones (Levin

et al. 2000, Sheley et al. 2004, Levin & Sainz-Borgo 2012,

Wojczulanis-Jakubas et al. 2015).

e exclusivity of use of the feeder (%Exc) was dened

as the percentage of time the individuals of a particular

species used the feeder without sharing it with individuals

of other species. Similarly, it was also calculated the per-

Table 1. Trials carried out to study the interactions between birds and their preferences for fruit types or feeder location.

e rst four treatments were carried out on Saturdays and Sundays and the recording sessions of the last two were carried

out on consecutive days.

Trial N° Fruits supplied Feeder location Recording days Sampling interval

1 Papaya-plantain Open sky 12 Dec-14-2019 to Jan-19-2020

2 Only papaya Open sky 6 Jan-25-2020 to Feb-9-2020

3 Only plantain Open sky 8 Feb-15-2020 to Mar-8-2020

4 Plantain-banana Open sky or under tree 12 Mar-14-2020 to Apr-20-2020

5 Mango-banana Open sky or under tree 9 Apr-25-2020 to May-3-2020

6 Mango Open sky 10 May 8-17-2020

Birds in an urban garden of Venezuela

centage of time a species share the feeder with individu-

als of its own species (%Own) in respect to the total time

shared with all individuals of same or dierent species.

In this research some variables were not under control,

as the progressive changes in rainfall frequency and tem-

perature associated with the advance of the dry season, and

the phenological changes of both plants (owering, fruit

and seed production) and birds, surely as a consequence

of the changes of the rst variable. We are aware that with-

out controls we cannot eliminate the possibility that some

factors other than those considered in this study may have

aected the results. Trials started in the early dry season

in December 2019 and ended in mid-May 2020, when

some sporadic rainfall had already occurred. roughout

the treatments, some birds were observed carrying food

from the feeder to their chicks, which was particularly no-

ticeable in the case of the Tropical Mockingbird (Mimus

gilvus), a species whose adults came down accompanied

by juveniles on numerous occasions. On the other hand,

Caimito (Chrysophilum sp.) fruits ripen in February 2020

and served as food for all the frugivores until the rst week

of March. e mango season started in April and possibly

other plants in the vicinity may have oered their fruit to

the birds. e peak of ripening of the Pomagás fruits oc-

curred in the second and third week of May. Some neigh-

bors also oer fruits or other food types to the birds, al-

though they do not do that routinely. All of these factors

may have inuenced the frequency of visits of dierent

bird species, but one can only speculate on the magnitude

of their eects.

A dominance matrix was produced (Levin et al. 2000,

Sainz-Borgo 2017) that shows the number of times that

the dierent species win (displace) or lose (are displaced)

their interactions in the feeder. e hierarchical struc-

ture obtained was correlated with the weight of the birds.

ese variables were in turn correlated with the exclusivity

of use of the feeder by each species (%Exc) and the per-

centage of time not shared with individuals of others spe-

cies (%Own).

Statistical analyses

e number of visits and the time spent by each species

in the consumption of the two pieces of fruits oered si-

multaneously were calculated and compared. Two-sample

paired tests (Wilcoxon) were performed to determine the

signicance of the dierences in times used by each species

in the consumption of the two pieces of fruit oered si-

multaneously. is test was also performed to compare the

frequency of visits to the feeder (v/min) on alternate days

when it was placed either beneath the open sky or under

the canopy of a tree.

Contingency tables analyses were performed to deter-

mine if the frequency of use of the feeder by solitary indi-

viduals or by birds in groups was independent of the way

the pieces of fruit were placed (together or separate). For

these analyses, the birds that rst arrived to the feeder in

each recording session were not included, since they are

inevitably alone at the time of arrival.

e dierences between the numbers of birds visiting

the feeder when the pieces of fruit were together or sepa-

rate were evaluated with a tests of simple proportions, un-

der the null hypothesis (Ho) that those numbers should

be proportional to the recording times (eort) in each

condition. Given that the recordings were started and

stopped manually, recording times in each condition were

not exactly identical, so that under the null hypothesis (no

eect) the proportion of birds expected when the pieces

were together, departed slightly from 0.5, as will be indi-

cated in each case.

Statistical analyses were carried out with the open ac-

cess program Past 4.02 (Hammer et al. 2001, Hammer

2020). e statistical results were rated as highly signi-

cant (P <0.01), signicant (0.01 ≤ P <0.05) or marginally

signicant (0.05 ≤ P <0.1).

RESULTS

A total of 203 recording sessions were carried out, with

a cumulative gross time of 27.6 hours and an eective du-

ration of 25.9 hours. Sixteen species of birds arrived at the

feeder for a total of 2,493 visits and a cumulative occupa-

tion time of 18.063 hours/birds (Table 2). ere was no

correlation between the average duration of visits and bird

weights (Spearman r

= 0.075, P = 0.80, n = 14). ere

were wide variations in the relative abundances of species

in the dierent trials, as will be shown later, but when the

results of all sessions are pooled together, individuals of

only three species, the Blue-gray tanager (raupis epis-

copus), the Pale-breasted thrush (Turdus leucomelas), and

the Tropical Mockingbird (M gilvus) accounted for 66%

of the total time spent by all species at the feeder. In con-

trast, eight species represented less than 10% of the total

accumulated time. e rst three mentioned species, to-

gether with the Yellow-rumped Cacique (Cacicus cela) and

Stripe-backed Wren (Capylorhynchus nuchalis) used the

feeder a high percentage the time without sharing it with

other species (%Exc). On the other hand, individuals of

some species, predominantly the Tropical Mockingbird,

shared the feeder mostly with individuals of their own

species (%Own) whereas other did not share it at all, as it

was the case with the thrushes (Fig. 2). Other species that

shared a high percentage of their time with individuals of

A. E. Seijas & S. F. Seijas-Falkenhagen

Alone M.gil T.epi T.pal T.leu S.cay Others

(5)

Mimus gilvus

Alone T.leu T.epi M.rub S.cay M.gil Others

(8)

Turdus leucomelas

Alone T.nud T.epi S.cay E.lan C.cel Others

(6)

Turdus nudigenis

Alone C.cel T.epi S.cay T.leu T.nud Others

(3)

Cacicus cela

Alone T.epi T.pal S.cay T.leu T.nud Others

(10)

Thraupis episcopus

Alone T.pal T.epi S.int S.cay M.gil Others

(9)

Thraupis palmarum

Alone S.fla T.epi S.cay E.lan R.car Others

(10)

Sicalis flaveola

Alone S.cay T.epi T.leu E.lan S.fla Others

(9)

Stilpnia cayana

Table 2. Use of the feeder by dierent species of birds and their relationship with their body weight. Total accumulated

time 18.063 hours. See denitions of %Exc and %Own in the text. Means in seconds. Body weights according to Hilty

(2003). When two gures of weight are oered, the rst is for the female the second for the male.

Species Visits

Time at the feeder

Weight (g)

Total (%) Mean (S.E.) %Exc %Own

Thraupis episcopus 949 24.78 17.0(0.54) 68.4 68.9 35

Turdus leucomelas 515 22.85 28.9(1.37) 76.4 0 62

Mimus gilvus 255 18.35 46.8(2.29) 86.0 91.6 54

Stilpnia cayana 186 7.44 26.0(1.57) 35.2 47.2 19

Cacicus cela 90 4.50 32.5(2.22) 61.5 23.0 60-104

Turdus nudigenis 107 4.19 25.5(3.37) 49.5 0 60

Thraupis palmarum 101 4.17 26.9(3.40) 24.2 34.9 36

Sicalis flaveola 79 3.83 31.5(2.61) 30.6 28.9 20

Euphonia laniirostris 75 2.69 23.3(2.13) 30.8 15.2 13.5

Saltator coerulescens 40 1.72 28.0(3.04) 50.3 12.1 55

Melanerpes rubricapillus 25 1.59 41.4(5.74) 13.0 0 48

Sporophila intermedia* 16 1.37 55.6(12.6) 9.1 0 12

Campylorhynchus nuchalis 38 1.20 20.6(1.79) 65.3 64.6 25

Coereba flaveola* 4 0.58 94.3(43.8) 5.8 0 9

Raphocellus carbo* 10 0.55 35.8(14.8) 0.6 15.0 25

Psarcolius decumanus* 3 0.19 40.7(18.7) 100 - 180-300

* Due to small sample size, data for these species were not analyzed.

Figure 2. Time spent at the feeder (as %) of each bird species as solitary individuals (alone, black bar), sharing with individuals of their

own species (white bar) or with other species (gray bars). Charts to the le are for birds relatively large (body weight of 54 g or more),

whereas those to the right belong to smaller birds (from 19 to 36 g). Notice that the Turdidae did not share the feeder with individuals

of their own species.

Birds in an urban garden of Venezuela

their own species were the Blue-grey Tanager (68.9%), the

Burnished-bu tanager (Stilpnia cayana; 47.2%) and the

Palm tanager (raupis palmarum; 35.07%). ere were

no correlations of %Exc and %Own with the weight of

the birds (n=12; r

= 0.399, P =0.199, and r

= -0.423,

P=0.171, respectively).

Bird interactions

e winner-loser dominance matrix (Table 3) shows

that the Yellow-rumped Cacique (Cacicus cela) and the

Tropical Mockingbird were the most dominant species.

However, in interactions between these two birds, it was C.

cela that won the majority of the encounters. At the base of

the hierarchical structure were the ick-billed Euphonia

(Euphonia laniirostris) and the Gray seedeater (Sporophila

intermedia), species between which no interactions were

recorded (Table 3). e hierarchy was positively correlat-

ed with the weight of the birds and with %Exc (n=12; r

0.745, P =0.005, and r

= 0.731, P =0.007, respectively).

Number and rate of visits

roughout the six trials, the relative importance of

each species at the feeder, measured either as visits per

hour (v/h) or as total accumulated time (in minutes) per

recording hour (min/h) was highly variable (Table 4).

ese measurements are highly correlated but not equiva-

lent, since there are dierences in the duration of the visits

among the species (see mean values in Table 2). In the rst

trial, for example, when v/h is used, T. episcopus duplicates

T. leucomelas; but if the unit of measurement is min/h,

then it is this last species that surpasses T. episcopus.

e number of total visits per hour (v/h) decreased

throughout the rst four trials, going from a maximum

of 186.4 v/h in in mid-December-mid-January (Papaya-

plantain) to near of a third of that gure (62.9 v/h) from

the end of March-beginning of April (Plantain-banana).

In the h trial (Mango-banana) the number of v/h in-

creased again (121.6 v/h) without reaching the levels of

the initial treatment, to decrease again to 47 v/h in the last

trial at mid-May (Only Mango).

No species showed a constant visit rate (v/h) or accu-

mulated occupation time (min/h) throughout the trials.

If we compare the changes in terms of accumulated time

(min/h), we have that both T. leucomelas and M. gilvus

increased their presence between the rst and second tri-

als (by 20.1% and 314.6%, respectively); but both spe-

cies decreased their presence in successive treatments and

reached the lowest values when only mango was oered.

e accumulated times for M. gilvus showed their maxi-

mum values in the second and third trials (19.9 and 15.3

Table 3. Winner-loser dominance matrix for species that visited the feeder. e column “Hierarchy” accounts for the

number of species for which the species heading each row won the majority of its interactions. e diagonal (underlined)

indicates the number of times that an individual was displaced by another of its own species. is last value is not included

in the accounts of “wins” or “losses”.

Winners

Losers

Win Lose Hierarchy

Cc Cn El Mg Mr Rc Scoe Sf Scay Si Te Tp Tl Tn

C. cela 7 2 4 14 2 0 1 0 6 0 20 7 14 6 76 4 10

C. nuchalis 0 0 0 0 1 0 0 1 3 0 2 0 7 2 16 7 5

E. laniirostris 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 34 0

M. gilvus 4 0 3 2 1 0 3 3 11 1 36 7 30 1 100 14 10

M. rubricapillus 0 0 0 0 0 0 0 0 1 0 5 0 7 1 14 4 4

R. carbo 0 0 0 0 0 0 0 1 0 0 1 0 0 0 2 7 2

S. coerulescens 0 0 2 0 0 0 2 0 1 0 10 1 5 1 20 6 6

S. flaveola 0 1 1 0 0 0 0 6 0 0 0 0 0 0 2 20 1

S. cayana 0 0 2 0 0 0 0 1 0 0 0 0 0 0 3 87 2

S. intermedia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0

T. episcopus 0 0 13 0 0 0 1 10 29 1 218 8 0 3 65 288 5

T. palmarum 0 0 2 0 0 0 0 1 0 2 6 0 0 2 13 42 4

T. leucomelas 0 3 5 0 0 7 1 2 36 2 184 18 77 32 290 64 8

T. nudigenis 0 1 2 0 0 0 0 1 0 0 24 1 1 2 30 48 3

A. E. Seijas & S. F. Seijas-Falkenhagen

min/h, respectively), when adults visited the feeder ac-

companied by juveniles as we will show later. In any case,

T. episcopus was the species that showed the widest uc-

tuations in visit rates (v/h) throughout the trials (Fig. 3),

particularly between the rst and second, with a decrease

of 98.5%. e changes in the total number of birds that

visited the feeder largely reect variations in the relative

abundance of this species.

e Tropical Mockingbird and the Blue-gray Tanager

were the species with the highest number of records of in-

dividuals carrying food from the feeder (Fig. 4). e maxi-

mum for M. gilvus in this regard (9.7 CF/hour) occurred

in late January to early February. e maximum number

of visits of the juveniles of this species (4.6 j/h) occurred

in the following trial, in between February-15 to March-8.

e Blue-gray Tanager’s carries occurred later, peaking at

the end of April-beginning of May (14.4 carries/hour)

but only a few juveniles of this species (0.2 j/h) could be

identied in the last trial, in mid-May, 2020. Pale-breasted

thrushes carrying food out of the feeder were observed in

between March-14 and May-3 and the rst juvenile visits

were observed in between May-8 to 17. In addition to C.

cela and S. cayana, individuals of other ve species carried

food in their bills or visit the feeder as juveniles in a very

low frequency and were not analyzed in detail.

Location of fruit pieces and feeder

In treatments with two pieces of the same fruit, birds

pecked more times from the piece on the right, the side of

the feeder facing to the garden (Wilcoxon paired test; n =

530, z = 2.996, P = 0.003). is behavior was especially

marked in the case of C. cela (n = 38, z = 3.716, P <0.001)

and of C. nuchalis (n = 12, z = 2.198, P = 0.028). If the

data for these two species are removed from the analyses,

the average time spent by the remaining birds eating from

the piece at the right side (17.423 sec/visit) was still great-

er than that spent on the piece on the le (14.743 sec/

visit), but the dierences were just marginally signicant

(n = 479, z = 1.757, P = 0.079).

Aer pooling the data of the rst three trials, when the

arrangement of the fruit pieces in the feeder were alter-

nated on consecutive recording days (the rst day together

and the next separate, or vice versa), there were a greater

number of visits to the feeder when the pieces of fruit were

separated (738) than when they were together (608). Sta-

tistical analyses were performed for each trial separately.

Table 4. Visits per hour of recording (v/h) and time spend at the feeder (min/h) by the dierent bird species in each one

of the trials. Values in parentheses (t

) represent the eective time recorded in each treatment.

Species

Papaya-plantain



Papaya



Plantain



Plantain-banana Mango- banana



Mango

= 4.357h) (t

= 2.584h) (t

= 3.699h) (t

= 5.740h) (t

= 4.527h) (t

= 4.998h)

v/h min/h  v/h min/h  v/h min/h  v/h min/h  v/h min/h  v/h min/h

C. cela 3.7 2.2 1.2 0.2 9.5 5.0 3.3 1.4 3.8 2.7 0 0

C. nuchalis 1.6 0.4 1.2 0.6 2.4 0.5 0.3 0.1 1.5 0.6 2 0.9

C. flaveola 0 0 0 0 0.0 0.0 0 0.0 0.7 1.1 0.2 0.3

E. laniirostris 1.8 0.4 0 0 0.8 0.2 2.6 0.8 10 4.6 0.6 0.3

M. rubricapillus 1.8 2 1.5 1 2.2 1.0 0.3 0.2 0.7 0.2 0 0

M. gilvus 4.8 4.8 22 19.9 19.2 15.3 8.7 5.6 12 7.8 0.8 0.5

P. decumanus 0.7 0.5 0 0 0.0 0.0 0 0.0 0 0.0 0 0

R. carbo 1.1 0.1 0 0 0.0 0.0 0 0.0 0.4 0.3 0.6 0.8

S. coerulescens 1.1 0.6 1.2 0.5 1.1 0.3 2.4 1.2 2.6 1.4 0.4 0.1

S. flaveola 0 0 0 0 0.3 0.0 0 0.0 6.4 3.7 9.6 4.9

S. intermedia 0 0 0 0 0.0 0.0 0 0.0 0.2 0.2 3 2.8

S. cayana 9.6 2.3 3.1 0.5 6.5 1.8 4.9 1.8 12 6.8 6.2 4.2

T. episcopus 99 21.7 1.5 0.1 7.6 1.9 24 8.0 57 16.1 17 9.5

T. palmarum 4.8 1.2 0.4 0 4.9 2.0 3 1.3 6.8 3.0 2.6 2.3

T. leucomelas 47 22.8 51 27.4 23.0 10.2 8.9 4.5 7.1 2.5 2.2 0.5

T. nudigenis 8.7 4 3.5 1.1 5.9 2.1 4.5 1.9 0.4 0.8 2 0.6

Globals 186.4 62.9  86 51.2  83.3 40.4  62.9 26.9  121.6 51.9  47 27.6

Birds in an urban garden of Venezuela

100

120

140

160

180

200

100

120

Plantain-papaya

(Dec 14-Jan 19)

Papaya

(Jan 25-Feb 9)

Plantain

(Feb 15-Mar 8)

Plantain-banana

(Mar 14-Apr 20)

Banana-mango

(Apr 25-May 3)

Mango

(May 8-May 17)

Visits per hour (v/h)

T. episcopus T. leucomelas M. gilvus Others All

Figure 3. Visits per recording hour (v/h) of the three most common bird species at the feeder in each one of the trails. e scale on the

right (v/h) is for all birds together.

Papaya &

plantain

(Dec-Jan)

Papaya

(Jan-Feb)

Plantain

(Feb-Mar)

Plantain &

banana

(Mar-Apr)

Mango &

banana

(Apr-May)

Mango

(May)

Carrying food per hour (CF/h)

C. cela M. gilvus T. episcopus T. leucomelas

0.0

1.0

2.0

3.0

4.0

5.0

Papaya &

plantain

(Dec-Jan)

Papaya

(Jan-Feb)

Plantain

(Feb-Mar)

Plantain &

banana

(Mar-Apr)

Mango &

banana

(Apr-May)

Mango

(May)

Juveniles per hour (J/h)

Figure 4. Above: Frequency of adults of some species leaving the feeder with food in their bills. Below: Frequency of juveniles visiting

the feeder.

In the Papaya-plantain treatment, the values for together:

separate were 355:461; a highly signicant disproportion

(expected proportion = 0.485; z = -2.834, P <0.005). In

the case of the trial with only Papaya the disproportion

(98:124) was signicant (expected proportion = 0.517;

z = -2.164, P = 0.030) and not signicant in the case of

only Plantain (155:153) (expected proportion = 0.493;

z = 0.364; P = 0.716). If the birds are divided into two

groups according to their weight, only for those <40g the

disproportion was signicant in the Papaya-plantain trial

(220:300; z = -2.809, P <0.005) and the Only papaya trial

(2:14; z = -3,136, P = 0.002). ere were no signicant

disproportions in any of the treatments for birds >40g

(P>0.1).

e way birds visited the feeder (in solitary or in com-

pany of other birds) was not independent of how the piec-

es of fruits were disposed (together or separated). at was

particularly so when the data of the three trials are pooled

together (Global data) (Pearson χ

= 11.431, P <0.001);

that is, the arrangement of the fruit pieces inuences the

A. E. Seijas & S. F. Seijas-Falkenhagen

frequency with which the birds are in the feeder alone or

accompanied by other birds (Table 5). e results of these

analyses when each trial is taken separately pointed in the

same direction, although the probability values in two of

them (Papaya-plantain and only papaya) are marginally

signicant.

Fruit preferences

In all the trials in which two type of fruits were of-

fered, three or more birds consumed one of the options

in a higher frequency than expected by chance. In the

rst treatment, the Blue-gray tanagers, Palm tanager,

and Yellow-rumped caciques consumed plantain in pref-

erence over papaya (Fig. 5A). Even though most species

decreased their feeder occupancy rate (min/h) in the next

trial (when only papaya, the non-preferred fruit in rst

trial was oered), these three species were the ones with

the more accentuated reduction, with decrease values of

99.5%, 90.1% and 100%, respectively. In contrast, T. leuco-

melas and M. gilvus, birds that had not shown preference

for papaya or plantain, increased their time in the feeder

(min/h) when it was oered only papaya, the rst of these

species in only 20.2%, but the Tropical Mockingbird did

it in 314.6%. Species with less than 12 visits were not used

in the analyses.

When plantain and banana were oered, ve species

preferred the rst fruit (Fig. 5B). However, when the

birds had to choose between banana or mango six species

favored the banana and only one, the Saron Finch (Si-

calis aveola), a species that have not consumed any fruit

in the four previous trials, ate almost exclusively mango

(Fig.5C).

In the last trial, when only mango was presented to the

birds, the Saron Finch was the second most common

species, only below to the Blue-gray Tanager. It is neces-

sary to point out that in the two tryouts in which mango

was oered, 15 species visited the feeder, the maximum

number in all this study. e three additional species that

appeared when this fruit was presented were the already

mentioned Saron Finch, the Gray Seedeater (Sporophila

intermedia), and the Bananaquit (Coereba aveola). ese

three species consumed exclusively mango.

Feeder location

In the fourth and h trials, the two pieces of food

were placed separated, but the location of the feeder was

alternated: one day at open sky and the next under a

tree canopy (or vice versa). ere were no dierences in

the frequency of bird visits between this two conditions

(Wilcoxon paired test: n =10; z = 1.23, P = 0.218). On

the other hand, there were positive correlations between

the cumulative times spent by each bird species (min/h)

when the feeder was located at the open sky or under the

tree (Table 6: Spearman Rank correlation: r

= 0.879,

P<0.001 for Plantain-banana; r

= 0.920, P < 0.001 for

Mango-banana).

DISCUSSION

Frequency of visits and preferences for fruit

In the ve months covered by this research (the entire

dry season) the relative frequency of bird species that vis-

ited the feeder was highly variable. Sixteen species visited

the feeder, but the number of species varied between 10,

in the second trial (when only papaya was oered) and 15

in the h (when mango and banana were oered). Taken

together the six trials carried out, only three species, the

Blue-gray tanager, the Tropical Mockingbird and the Pale-

breasted thrush, accounted for the vast majority of visits,

with a maximum that exceeded 80% in the rst two treat-

ments and a minimum of 42% in the last one. is domi-

nance is comparable to the one reported by Galbraith et al.

(2017) for feeder in Auckland, New Zealand, but in their

case, two of the three dominant species were exotic.

roughout the study, the type of fruit oered varied,

and due to the abrupt changes between one trial and the

one that followed, it is unavoidable to conclude that in

Table 5. Frequency of bird visiting the feeder in solitary or accompanied by other birds when the pieces of fruit were to-

gether or separated. Results of the analysis with contingency tables (Chi-square).

Global data  Papaya-plantain  Only papaya  Only plantain

Together Separated  Together Separated  Together Separated  Together Separated

In solitary 286 286 120 130 70 77 96 79

Accompanied 273 402 214 309 17 35 42 58

Pearson χ

11.431 3.457 3.478 4.209

P value <0. 001  0.063  0.062  0.040

Birds in an urban garden of Venezuela

0 3 6 9 12 15 18 21 24

Others

T. palmarum

M. rubricapillus

C. cela

S. cayana

T. nudigenis

M. gilvus

T. episcopus

T. leucomelas

Papaya

Plantain

0 3 6 9 12 15 18 21 24

Others

S. coerulescens

T. palmarum

C. cela

S. cayana

T. nudigenis

T. leucomelas

M. gilvus

T. episcopus

Banana

Plantain

0 3 6 9 12 15 18 21 24

Others

T. leucomelas

C. cela

T. palmarum

S. flaveola

E. laniirostris

S. cayana

M. gilvus

T. episcopus

Cummulative time (min/h)

Banana

Mango

Figure 5. Time spent by birds at the feeder consuming dierent

fruits. At the end of the bar is indicated if the dierences are

signicant (*) or highly signicant (**).

Table 6. Cumulative time at the feeder (min/h) by die-

rent bird species when it was located at open sky or under

a tree canopy. Eective recording time for each trial and

condition in shown in parentheses.

Species

Plantain-banana Mango-banana

Open sky

(2.90h)

Under a

tree (2.84h)



Open sky

(1.98h)

Under a

tree (2.03h)

C. cela 1.018 1.760 1.010 3.399

C. flaveola - - 2.525 0.000

C. nuchalis 0.000 0.246 0.732 0.418

E. laniirostris 1.052 0.475 3.004 6.897

M. gilvus 6.273 4.992 8.020 6.725

M. rubricapilus 0.477 0.000 0.446 0.000

R. carbo - - 0.000 0.696

S. coerolescens 1.035 1.320 1.018 1.491

S. flaveola 0.017 0.000 4.418 4.005

S. intermedia - - 0.446 0.000

S. cayana 1.644 2.030 6.404 8.568

T. episcopus 8.343 7.732 15.619 14.883

T. palmarum 1.489 1.097 3.854 2.310

T. leucomelas 4.180 4.887 2.281 3.104

T. nudigenis 1.230 2.605 1.161 0.541

All 26.760 27.143  50.937 53.038

some cases the type of fruit(s) placed in the feeder deci-

sively inuenced the frequency of visits of some species.

at was clearly the case of the last two trials, when mango

was oered to the birds. e Saron Finch did not visit

the feeder in any of the previous four tryouts, despite the

fact that this species is a permanent occupant of the garden

(Seijas & Seijas-Falkenhagen 2020). Visits of S. aveola to

the feeder began in the h trial, when mango was oered

as one of the options, and the relative importance of this

bird reached to 20.4% of the total visits when that fruit

was oered in exclusivity, only below the Blue-gray Tana-

ger, with 35.7 % of visits.

It is necessary to discuss a little more our ndings with

S. aveola, a species regarded as granivore (Hilty 2003,

Sainz-Borgo et al. 2018). is is a very common species in

the garden and throughout the city of Guanare (Seijas et

al. 2011, Seijas & Seijas-Falkenhagen 2020). During this

investigation, dozens of individuals were permanently ob-

served foraging in the lawn, a few meters from the feeder.

We have already reported that S. aveola consumes fruits,

and we keep photographs of some individuals eating papa-

ya and banana at the feeder, as well as fruits of Chrysophi-

lum sp. on the tree. However, those observations were not

properly evaluated. e only reference we found in the lit-

erature on the consumption of fruit by the Saron Finch

was that of Soriano et al. (1999) who reported evidence of

consumption of a cactus fruit by this species. It is worth

mentioning that this nch has also been observed catching

ying termites.

It was another surprise to observe the Grey seedeater

(Sporophila intermedia) consuming mango. In the 16

records of visits of this bird to the feeder it was always a

female, probably the same individual. Hilty (2003) indi-

cated that, unlike other Sporophila, S. intermedia has quite

varied eating habits that include insects, even caught in

ight. e other species that only went down to consume

mango was the Bananaquit, although only four times.

Another unexpected visitor to the feeder was C. nuchalis,

A. E. Seijas & S. F. Seijas-Falkenhagen

a species regarded as an insectivore (Phelps 1999, Sainz-

Borgo et al. 2018).

Changes in the frequency of Blue-gray Tanager are more

dicult to associate exclusively with the type of fruit oered.

It was the most abundant species in the rst trial (Plantain-

papaya) and practically disappeared from the feeder when

it was oered exclusively papaya, fruit that had not been its

favorite in the previous trial; but this bird did not show the

return that would have been expected when plantain was of-

fered again. e relative importance of T. episcopus increased

in the fourth and h treatments, to show a further decrease

when only mango was oered. We believe that, in addition

to the type of fruit oered, these uctuations were inu-

enced by the presence of the Tropical Mockingbird. is

last bird is at the top of the hierarchical structure among the

birds that visit the feeder. It exercises its dominion very ag-

gressively. e v/h of the Tropical Mockingbird increased

more than four-fold between the rst and the second tri-

als, when the juveniles started visiting the feeder with their

parents. At these times, adults Tropical Mockingbirds seem

to be particularly feisty and intolerant to the presence of

other birds. Although the Blue-gray Tanager (and also the

Palm Tanager) consumes papaya, perhaps accessing that

non-preferred fruit would mean to compete with M. gilvus,

which would imply an eort that would not oset the ben-

ets obtained in terms of energy and nutrition. When the

Tropical Mockingbird prominently occupied the feeder, in

the second and third trials, not only did T. episcopus decrease

its presence, so did most of the small species, among which it

is worth noting the Burnished-bu Tanager, which reduced

its presence in a 78.3%.

It could be argued that T. leucomelas could also have

inuenced the reduction in the number of visits to the

Blue-gray Tanager and other birds, but the increase in the

occupation time of the Pale-breasted thrush was of only

20.2% between the rst and second trials. Rather, this

small increase could be due to the drastic reduction in the

number of T. episcopus visits, because it would lighten the

burden on the rst species of competing with a very nu-

merous bird. In support of this argument is the fact that

the mean time of T. leucomelas visits between these two tri-

als increased, although the dierence was not signicant.

In addition, there were 137 interactions between these

two species in the rst trial, all of them won by T. leuco-

melas, which did not prevent T. episcopus from being the

most frequent species in the initial treatment. e marked

decline in the time of occupation of T. leucomelas aer the

second trial is dicult to explain and could have some

relationship with the reproductive activity of the species,

whose courtship, nesting, incubation and chick atten-

dance take place in the rst months of the year (Seijas &

Seijas-Falkenhagen 2020). Klem (2008) noted that birds

in northern latitudes increase their frequency of visits to

feeders when they are not breeding. is could be the case

of the Pale-breasted rush in our study, but we have al-

ready seen that in the case of the Tropical Mockingbird

frequency of visits increased considerably when the species

was raising its chicks.

Surely all species respond by increasing or decreasing

their frequency of visits to the feeder based on the exis-

tence or not of alternative feeding sources in the vicinity,

as has been documented for frugivorous birds in dierent

regions of the Neotropics (Leck 1972, Fleming 1979). An

increase in the number of visits of some birds would have

been expected when only plantain was placed in the feeder

(as of February 15, 2020), the fruit that had been selected

in preference by Blue-grey Tanager, Yellow-rumped Caci-

que and Palm Tanager in the rst trial. is was not the

case, as discussed in previous paragraphs. One factor that

could have inuenced this ‘no return’ was the entry into

full production of fruits of a Caimito (Chrysophilum sp.)

tree (aer February 8) just 20 meters from the feeder. e

production of this tree was very copious (personal obser-

vation). All the species that visit the feeder were observed

consuming this fruit and the most abundant of them was

T. episcopus. e production of caimitos ended at the be-

ginning of March, however, this fact was not reected in

the number of birds visiting the feeder in the trial that

was carried out immediately (when Plantain-banana were

oered), since though the visit rate of C. cela increased

slightly compared to the previous trial, the number of v/h

of other species, especially T. leucomelas and M. gilvus con-

tinued to decline.

e disappearance of C. cela from the feeder when only

papaya was oered cannot be explained by the presence of

M. gilvus, since Yellow-rumped Cacique dominates over

the Tropical Mockingbird (and over all the other species

with which it interacts). It is possible that the almost zero

consumption of papaya by this icterid is a consequence of

the characteristics of its beak, which may not be very e-

cient for eating this fruit. is of course is speculative, but

the 16 species that visited the feeder show wide variation

in bird size and shape, and there is likely to be a close rela-

tionship between the size and shape of the birds’ beaks, on

the one hand, and foraging activities, on the other (Kantak

1979, Grant 1986, Foster 1987). In this sense, the clear

preference of S. aveola and S. intermedia for mango could

also be due to the possession of ecient picks to cut the -

bers of this fruit. Preferences may be based on, or depend

on, the protein and nutritional content of the fruits (Levey

1987, Schaefer et al. 2003, Corlett 2011) or on which oth-

er food sources are or are not available in the vicinity at the

Birds in an urban garden of Venezuela

same time. Bosque & Calchi (2003), for example, pointed

out that in captivity, the T. episcopus is able to discriminate

between diets with dierent protein percentage and select

the one with the highest protein content. We did not ob-

tain information on the protein content of the banana, but

the aforementioned authors indicated that those of the

banana and the papaya are 3.5% and 5.1%, respectively.

If the protein content of the plantain is similar to that of

the banana, then it is surprising that the Blue-grey Tana-

ger preferred this fruit instead of the papaya. To nish this

discussion of fruit preferences is interesting to note that S.

cayana was the most generalist species of all, not showing a

preference for any of the options oered.

Dominance and timeshare

It must be taken into account that the pie charts where

the accumulated times in the visits of all the birds are

shown and compared (Fig. 2) were elaborated from trials

carried out over more than ve months, during which the

fruits presented to the birds were periodically changed.

e chart would look be very dierent if each of the trials

carried out were analyzed separately, as evidenced in Fig.

3. is warns of the risk of drawing conclusions based on

very short-term studies and that it is necessary to continue

investigating the dynamics of the assembly of birds that are

attracted to the feeder and the factors that inuence that

dynamics.

e dominance of the species was mainly determined

by their sizes, as has been shown in several bird studies

(Wallace & Temple 1987, Shelley et al. 2004, Wojczulanis-

Jakubas et al. 2015, Galbraith et al. 2017). Relatively large

species do not share much the feeder with individuals of

other species. Relatively small species, on the other hand,

showed few negative interactions among them and gener-

ally share the feeder, a strategy that allows them to consume

the fruits in the occasions where larger and dominant spe-

cies are out of the feeder. In the case of the Turdidae, our

results dier from those of Sainz-Borgo (2017) who found

that T. leucomelas and T. nudigenis share most of their time

at the feeder with other bird species, but this author reg-

isters her data in the aernoon (from 15:00-17:00). It is

possible that early in the morning birds are less prone to

share the feeder because they may be hungrier than in the

aernoon, aer they have been several hours foraging.

Behavior also plays a very important role in the estab-

lishment of the hierarchies, when we see that individuals

of an aggressive species like M. gilvus largely dominates in-

dividuals of species slightly larger than them, such as those

of the genus Turdus. In the case of the Tropical Mocking-

bird, its dominance seems to increase when the species

goes to the feeder with its ospring.

MANAGEMENT RECOMMENDATIONS

e results of this study show that it is possible to ma-

nipulate the functioning of the feeder to: 1) increase the

diversity of species and the number of individuals that visit

it; 2) to favor those desirable species, and create conditions

not to attract undesirable ones. All the species that ap-

proached the feeder are native and although none of them

is threatened in any degree, several are aected by the ur-

banization process, if we take into account their absence

or scarcity in more central areas of the city of Guanare, ac-

cording to the study by Seijas et al. (2011). is is the case

of large birds such as the Crested Oropendola (Psaracolius

decumanus) and the Yellow-rumped Cacique; or medium

and small size birds such as the Silver-beaked Tanager

(Ramphocellus carbo) or the ick-billed Euphonia. Ac-

cording to the aforementioned study, very common spe-

cies in the city also came to the feeder, such as the Tropical

Mockingbird, the Blue-gray Tanager or the Saron Finch;

but the use of fruits exclusively to attract birds to the

feeder, we suppose, have kept away omnivorous birds such

as the domestic pigeon (Columba livia) and the Grackle

(Quiscalus lugubris), species very common in Guanare.

We found that both the type of fruit oered and the

way the pieces are arranged in the feeder inuence the

abundance and diversity of species that visit it, and al-

though there is still much to know about how these vari-

ables interact, an obvious recommendation is to place sev-

eral types of fruit simultaneously and to separate them, to

reduce negative interactions among birds. In the few rec-

ommendations that have been published in Venezuela on

the installation of bird feeders, the convenience of locating

them near bushes or even in the shade of trees has been

pointed out (Phelps 1999, Caula & Manara 2015). In our

study we did not detect dierences in the abundance and

variety of birds that visit the feeder when it was in the open

sky or under the shade of a tree, but our observations were

always made during the rst hour aer sunrise. Practical

reasons, such as protecting food from drying out or from

rain, suggest that placement in the shade is convenient.

is research on birds visiting a feeder is only intended

to be a beginning. Hopefully, it will encourage other re-

searchers to conduct new studies that overcome its failures

and limitations to answer new questions. In our case, the

execution and analysis of new eorts to cover the rainy sea-

son are pending.

ACKNOWLEDGEMENTS

Two anonymous referees made useful observations and

recommendations on earlier versions of this paper.

A. E. Seijas & S. F. Seijas-Falkenhagen

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