Revista de Biología Tropical, ISSN: 2215-2075, Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. 10, 2023)

Foraging ecology of the bird Eupsittula canicularis

(Psittaciformes: Psittacidae) in a modified Mexican landscape

Itzel Flores-Yllescas1; https://orcid.org/0009-0002-6961-1830

Miguel Ángel De Labra-Hernández2*; https://orcid.org/0000-0002-0361-4919

1. Licenciatura en Biología, Universidad del Mar, campus Puerto Escondido, Km 2.5, Carretera Federal Puerto

Escondido-Sola de Vega, 71980, San Pedro Mixtepec, Oaxaca, México; flowers.itzel@gmail.com

2. Instituto de Ecología, Universidad del Mar, campus Puerto Escondido, Km 2.5, Carretera Federal Puerto Escondido-

Sola de Vega, 71980, San Pedro Mixtepec, Oaxaca, México; ma.delabrah@zicatela.umar.mx (*Correspondence).

Received 09-XI-2022. Corrected 29-III-2023. Accepted 13-VI-2023.

ABSTRACT

Introduction: Seasonal phenological variations in tropical forests cause changes in food resource availabil-

ity. Animals use foraging strategies to follow the food supply in these settings. The Orange-fronted Parakeet

(Eupsittula canicularis) mainly inhabits the tropical dry forest of the Mexican Pacific to Northwest Costa Rica,

although little is known about its diet and foraging strategies.

Objective: To assess spatial variability in food resource abundance, diet, and foraging behavior of the Orange-

fronted Parakeet in a modified landscape in Oaxaca Coast, Mexico.

Methods: 30 phenology transects (200 × 6 m) were established during the dry season (February-June 2019) to

measure food resource availability in primary deciduous, semi-deciduous, and secondary forests. The Orange-

fronted Parakeets diet was determined by focal foraging observations, and dietary niche breadth and resource

selection were considered to determine feeding strategies.

Results: Orange-fronted Parakeets fed on fruits (42.3 %), seeds (29.3 %), and flowers (28.4 %) of 13 plant

species and presented a broad dietary niche breadth with a higher frequency of foraging in primary forest. The

Orange-fronted Parakeets select resources and adapt their foraging strategies based on food resource availability

in each habitat.

Conclusions: The study findings highlights the need to maintain the complete forest structure in a modified

landscape to ensure food resources availability for Orange-fronted Parakeets during the breeding season.

Key words: conservation; dietary niche; foraging strategies; Hurlbert index; primary forest; Psittacidae.

RESUMEN

Ecología de forrajeo del ave Eupsittula canicularis (Psittaciformes: Psittacidae)

en un paisaje mexicano modificado

Introducción: Los bosques tropicales presentan variaciones estacionales fenológicas provocando cambios en la

disponibilidad de los recursos alimenticios. Bajo estas condiciones, los animales emplean estrategias de forrajeo

al seguir la oferta del alimento. El perico frente naranja (Eupsittula canicularis) habita principalmente en el

bosque tropical caducifolio desde el Pacífico mexicano hasta Costa Rica, sin embargo, su dieta y estrategias de

forrajeo son poco conocidas.

Objetivo: Evaluar la variabilidad espacial en la abundancia de recursos alimenticios, la dieta y el comportamien-

to de alimentación del perico en un paisaje modificado de la costa de Oaxaca, México.

https://doi.org/10.15517/rev.biol.trop..v71i1.52180

TERRESTRIAL ECOLOGY

2Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. l0, 2023)

INTRODUCTION

Seasonal tropical forests exhibit a signifi-

cant variation in plant phenological, causing

temporal patterns in fruit availability through-

out the year (Bullock & Solis-Magallanes,

1990; Morales-Pérez, 2005; Quigley & Platt,

2003). Under these conditions, animals may

employ different foraging strategies in response

to changes in food resource availability (Flem-

ing, 1992; Leighton & Leighton, 1983). Psit-

taciformes (cockatoos, macaws, parrots, and

the like) feed on fruits, seeds, and flowers of

different plant species (Galetti, 1993; Renton,

2001; Renton et al., 2015), which show high

phenological variability in their productivity

(Hilty, 1980; Loiselle & Blake, 1991). Given

the variation in the food supply, parrots make

seasonal movements between habitats, and

they show fluctuations in local abundance

and dietary switching (Renton et al., 2015). In

addition, parrots can adjust the dietary niche

breadth or select resources according to food

resources abundance (De Labra-Hernández &

Renton, 2019; Díaz et al., 2012; Renton, 2001;

Robinet et al., 2003). However, the continu-

ous degradation of the tropical forests that the

parrots inhabit causes landscapes with food

resources distributed in discontinuous patches

of remnant forest (Laurance, 1999; Saunders,

1990). Therefore, generating information on

the availability and use of food resources in

modified landscape is essential to identify

foraging areas and the most important plant

species in the diet of parrots populations (De

la Parra-Martínez et al., 2019; Rivera et al.,

2020). Thus, these data can be used as a con-

servation tool for this critically endangered

group of birds (Berkunsky et al., 2017; Olah

et al., 2016).

The Orange-fronted Parakeet (OFP) (Eup-

sittula canicularis) has a wide distribution

from the Mexican Pacific slope (Southeast of

Sinaloa) to Northwestern Costa Rica (Forshaw,

1989; Howell & Webb, 1995). It is one of the

most common psittacines in the deciduous

and semi-deciduous tropical forest and is con-

sidered endemic to Mesoamerica (Palomera-

García, 2010). However, the rapid destruction

of its habitat (e.g. 48.6 % loss of OFP historical

distribution area in Mexico) due to the conver-

sion of primary forests to secondary vegetation

and illegal poaching have caused a population

decline (BirdLife International, 2018; Cantú-

Guzmán et al., 2007; Monterrubio-Rico et

al., 2016; Pires, 2012). Despite this, there are

information gaps on the OFP foraging ecol-

ogy. In Mexico, there are lists of different plant

species that are part of the OFP diet (De la

Parra-Martínez et al., 2016; Eguiarte & del Río,

1985; Palomera-García, 2010). Additionally,

it has been reported that, in degraded areas,

the species can feed resources from corn, sor-

ghum, and fruit crops (González-Gómez, 2018;

Palomera-García, 2010). However, OFP forag-

ing strategies in modified landscapes have not

yet been assessed.

Métodos: Se establecieron 30 transectos para estudios fenológicos (200 × 6 m) durante la época seca (febrero-

junio 2019) para determinar la disponibilidad de recursos alimenticios en el bosque tropical caducifolio, subca-

ducifolio y la vegetación secundaria. La dieta del perico se determinó mediante observaciones del forrajeo, y se

consideró la amplitud del nicho alimenticio y la selección de recursos como estrategias de forrajeo.

Resultados: En el área de estudio, el perico consume frutos (42.3 %), semillas (29.3 %) y flores (28.4 %) de 13

especies arbóreas y presenta un nicho alimenticio amplio con mayor frecuencia de forrajeo en el bosque primario.

El perico selecciona recursos y ajusta sus estrategias de forrajeo de acuerdo a la disponibilidad del alimento en

cada hábitat.

Conclusiones: Los resultados del estudio resaltan la necesidad de mantener la estructura completa del bosque en

paisajes modificados para asegurar la disponibilidad de recursos alimenticios para para el perico frente naranja

durante la época reproductiva.

Palabras clave: bosque primario; conservación; estrategia de forrajeo; índice de Hurlbert; nicho alimenticio;

Psittacidae.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. 10, 2023)

In Mexico, anthropogenic activities have

severely degraded the tropical deciduous forest

(De Jong et al., 2010; Trejo & Dirzo, 2000). In

the state of Oaxaca, it is estimated that tropical

deciduous forest covers an area of 26 731 km2

(28.8 % of the state), but only 52.4 % remains

preserved (Meave et al., 2012). On the coast

of Oaxaca, particularly in the municipality of

Santa María Colotepec, where this study was

carried out, 67.8 km2 of primary forest were

deforested between 2000 and 2011, while agri-

cultural and livestock areas increased by up

to 75 %; 36.9 km2 and 44.7 km2, respectively

(Leija-Loredo et al., 2016). The loss of primary

forests could modify the food resource avail-

able for the OFP. Therefore, this study aims to

determine spatial variability in food resource

abundance, diet, and foraging behavior (par-

ticularly dietary niche breadth and resource

selection) of OFP in a modified landscapes in

Oaxaca Coast, México.

MATERIALS AND METHODS

Study site: The study was carried out in

the Coastal region of Oaxaca in Mexico, spe-

cifically in the town of Camalote (15°56’03’’ N

& 96°52’27’’ W) and Corozalito (15°54’09’’ N

& 96°49’58’’ W) belonging to the municipality

of Santa María Colotepec, covering an area of

30.7 km2. These localities have both conserved

areas of primary forest (tropical deciduous and

semi-deciduous forest) and degraded areas

made up of pastures, crops, and secondary for-

est. The climate is warm and subhumid, with

rains in summer (Aw0), and the temperature

varies between 24-28 °C. The dry season occurs

from November to May, while the rainy season

occurs from June to October; precipitation var-

ies between 800-2 000 mm (Trejo, 2004).

The predominant vegetation is decidu-

ous forest (DF), where tree species measur-

ing between 7-15 m in height, such as Ceiba

parvifolia, Guaiacum coulteri, Bursera sp.,

Guazuma ulmifolia, and Jacaratia mexicana

(Rzedowski, 2006). In addition, semi-decidu-

ous forest (SDF) is present in the most humid

areas, such as ravines and along rivers, with

20-30 m tall trees such as Tabebuia rosea,

Bursera simaruba, Ficus insipida, Astronium

graveolens and Homalium trichostemon (Rze-

dowski, 2006). In recent decades, 67.8 km2 of

primary forest were deforested (Leija-Loredo

et al., 2016), and most of this area is now sec-

ondary forest in different stage of succession.

Food resources availability: On each for-

est types (DF, SDF, and SF), 30 phenology

transects (200 × 6 m) were established to deter-

mined food availability for the OFP (Chapman

et al., 1994). From February to June 2019, 250

fruiting trees with a diameter at breast height

(DBH) ≥ 10 cm were marked and monitored

to record DBH and estimated fruit abundance

index was measured by multiplying tree DBH

by the proportion of fruits in the canopy of

each tree (Boyes & Perrin, 2010; Chapman

et al., 1994). In order to make comparisons

between forest types, the following variables

were considered in each phenology transect:

(1) number of fruiting trees, (2) number of

fruiting tree species, and (3) fruiting abundance

index. Tree species were identified in the field

or using botanical sampling collected for later

identification at the Laboratory of Biological

Collections of the Universidad del Mar, campus

Puerto Escondido, Oaxaca, with the help of

specialized bibliography (García-Mendoza &

Meave, 2011; Pennington & Sarukhán, 2005;

Pérez & Barajas-Morales, 2011; Salas-Morales

et al., 2003; Salas-Morales et al., 2007).

Orange-fronted Parakeet diet: The OFP

diet was determined by focal observations of

feeding activity during the first four hours

after sunrise (06:30-10:30 h, N = 112 hours of

observation), along different survey routes in

the same areas where phenology transects were

established. Each survey route was visited once

a week from February to June 2019. Forag-

ing records were obtained by walking in one

direction within the routes and stopping only to

record OFP feedig activity. In addition, oppor-

tunistic observations were considered when

observing the OFP feeding off the routes and

during evening observations. For each foraging

4Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. l0, 2023)

activity, date, time, habitat type, number of

parakeets, tree species, and tree part consumed

(fruit, seed, leaf, flower or wood) were record-

ed. A single foraging record was considered

when observing one or more parakeets feeding

in a tree; when the parakeets change to another

resource item or tree, it was considered a sec-

ond feeding record (Galetti, 1993).

Data analysis: Data from the phenology

transects were used to determine food resource

abundance and availability for the OFP. Shap-

iro-Wilk normality tests were applied of data

from the phenology transects. Number of fruit-

ing trees variable presented a normal distri-

bution, while the fruiting abundance index

presented a normal distribution only after log

transformation. For this reason, analysis of

variance (ANOVA) was applied to determine

spatial (DF, SDF, and SF) differences in food

resource availability with the post hoc Tukey-

Kramer test (Zar, 1999). The number of fruiting

tree species was not normally distributed even

after log transformation. Therefore, a non-

parametric Kruskal-Wallis test was applied to

determine food resource availability between

forest types (Zar, 1999). Analyses were per-

formed in R version 3.3.0 (R Core Team, 2016).

To assess the OFP dietary niche breadth,

standardized Levin’s index was estimated as

Best = (B–1) / (n–1) where: B is Levin’s index

that includes the proportion of parakeets that

fed on each resource, and n is the number of

resources used (Krebs, 1999; Levins, 1968).

Index expresses the breadth of the niche on

a scale that varies from 0 (narrow niche),

indicating that the use is concentrated on few

resources, to 1 (broad niche), indicating that

the use is equally distributed over the resources

used (Colwell & Futuima, 1971). On the other

hand, Hurlbert niche index (Hurlbert, 1978)

was calculating to evaluated the OFP dietary

selection, which estimates the niche breadth

considering the proportion used and the avail-

ability of each resource. Index is expressed as

Ha = Σ(pij/âi) where: pij is the proportion of the

resources used by the parakeets and âi is the

quantity or availability of each resource (Krebs,

1999). In this case, a value close to 0 indicates

dietary selection, while a value close to 1 indi-

cates that dietary resources are consumed based

on availability, without selection. Additionally,

G-test with 95 % Bonferroni confidence inter-

vals (CI) was performed to determine whether

use of resources by the OFP differed signifi-

cantly from that expected by their availability

in each forests type, and to determine whether

the frequency of foraging by OFP recorded in

each forests type corresponded to that expected

according to the fruiting abundance index

(Byers et al., 1984; Neu et al., 1974).

RESULTS

Food resources availability: A total of

34 tree species grouped into 20 families were

recorded in the phenology transects. Species

richness was higher in DF (N = 21 species),

followed by SDF (N = 18 species), and SF

(N = 9 species). Considering the three forest

types, the Fabaceae family predominated with

nine trees species. In the DF, the most abundant

tree species were Jacaritia mexicana (N = 25

trees; Caricaceae), Cocholspermum vitifolium

(N = 22 trees; Cochlospermaceae), and Gua-

zuma ulmifolia (N = 16 trees; Malvaceae). In

the SDF, the most abundant tree species were

Homalium trichostemon (N = 29 trees; Salica-

ceae), Inga vera (N = 19 trees; Fabaceae), and

Bursera simaruba (N = 17 trees; Burseraceae).

While in the SF, the most abundant tree species

were G. ulmifolia (N = 17 trees) and Helio-

carpus pallidus (N = 13 trees; Malvaceae).

ANOVA analyses demonstrated significant dif-

ferences for the number of fruiting trees by

forest types (F2,27 = 10.6, P < 0.001); the DF

had significantly higher fruiting trees during

February and March (Fig. 1A). Nevertheless,

the number of fruiting tree species by forest

type did not differ significantly (H2 = 0.01, P

> 0.05, Fig. 1B). Regarding the fruiting abun-

dance index, there were statistically significant

differences between forest types (F2,27 = 5.7,

P = 0.008); the SDF had significantly higher

food resources availability mainly during April

to June (Fig. 1C).

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. 10, 2023)

Orange-fronted Parakeet diet: During

the study period, 41 OFP feeding records (N =

201 individuals) was obtained on 13 plant spe-

cies from 10 families (Table 1). Of the all OFP

feeding records, 42.3 % (N = 85 parakeets) cor-

responded to fruits, 29.3 % (N = 59 parakeets)

to seeds, and 28.4 % (N = 57 parakeets) flow-

ers. Regarding the forest types, the principal

items consumed in DF were fruits of F. cotini-

folia (39.5 %), and seeds of Bursera sp (29.6

%). In the SDF, the most frequent food item

were fruits of F. insipida (32.8 %), followed

by flowers of H. trichostemon (28.6 %), and

seeds of B. simaruba (21.4 %). In the SF, the

main foot item were fruits (pulp) of Mangifera

indica (29.3 %), followed by the seeds (20.7 %)

of G. ulmifolia, along with flowers (11.7 %) of

G. sepium.

Dietary niche breadth and resource

selection: The niche breadth was broad (Best =

0.619), with seven plants contributing > 5 % of

Fig. 1. Mean (± SD) of the availability of food resources in three forests types in Santa María Colotepec, Coast of Oaxaca,

Mexico during the middle to end dry season. A. number of fruiting trees, B. number of fruiting species, C. fruiting

abundance index (Σ DBH x the proportion of fruits in the canopy). Different letters on the bars indicate significant

differences (Tukey-Kramer, P < 0.05).

6Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. l0, 2023)

the OFP diet. Nevertheless, F. cotinifolia (19.4

%), and G. sepium (18.4 %), were consumed

more by the OFP. However, differences in the

dietary niche breadth were found when separat-

ing the analysis by forest types. In the DF, the

niche breadth was moderately (Best = 0.505)

which indicates that the OFP generally uses

few food resources, where F. cotinifolia, G.

sepium, and Bursera sp. contributed > 5 % of

the diet. In the SDF, the niche breadth was nar-

rower (Best = 0.450), the use of food resources

by the OFP is concentrated on few resources;

where F. insipida and H. trichostemon had the

highest number of parakeets feeding (N = 44).

In the SF, the niche breadth remained broad

(Best = 0.637), with four species (M. indica, G.

sepium, B. crassifolia, and G. ulmifolia) repre-

senting > 5 % of the OFP diet.

Hurlbert niche index was narrower (Ha =

0.295), which suggests that the OFP selects

food resources (G11 = 58.5, P < 0.001). Bonfer-

roni 95 % CI (Table 2), showed that in DF, the

OFP consumed F. cotinifolia, G. sepium, C.

spinosa, Bursera sp., F. insipida, and Bursera

sp., more than expected from their availability

(Fig. 2A). Also, J. mexicana is consumed in a

significantly lower proportion than expected

(Fig. 2A). In SDF, F. insipida and F. cotinifolia

are consumed in more significant proportion

than expected from their availability (P < 0.05,

Fig. 2B). Also, H. trichostemon and B. sima-

ruba are consumed in a significantly lower

proportion than expected (Fig. 2B). In SF, M.

indica and B. crassifolia are consumed in more

significant proportion than expected from their

availability (Fig. 2C). Also, G. ulmifolia is con-

sumed in a significantly lower proportion than

expected (Fig. 2C). Conversely, the consump-

tion of all other plant species did not differ

significantly from that expected according their

availability (Fig. 2C).

The frequency of OFP foraging records

differed significantly in each forest type (G2

= 34.3, P < 0.01, Fig. 3). In particular, the

Bonferroni 95 % CI indicate that OFP feeds

more in the DF (Pobs = 0.40, 95 % CI = 0.293-

0.583) in accordance with the greater fruiting

abundance index (Pesp = 0.27). In the SDF, OFP

feeds a significantly lower proportion (Pobs =

0.33, 95 % CI = 0.195-0.471) than expected

from their availability of food resources (Pesp

= 0.54, P < 0.05). Finally, in the SF, OFP feeds

(Pobs = 0.29) did not differ significantly from

that expected (Pesp = 0.18; P > 0.05); the OFP

Table 1

Tree species that are part of the diet of Eupsittula canicularis during the middle to end dry season in Santa María Colotepec,

Oaxaca. In addition, number of foraging records, number of individuals feeding, tree part consumed, and date of the record

are included.

Family / Species Common name Tree part

consumed

Foraging

records

Number

of parrots Month

Anacardiaceae / Mangifera indica Mango Fruit (pulp) 4 17 April May

Burseraceae / Bursera simaruba Palo mulato Seed 5 16 March/May

Burseraceae / Bursera sp. Copal Seed 1 6 April

Caricaceae / Jacaratia mexicana Bonete Seed 2 4 April

Fabaceae / Gliricidia sepium Cacahuanano Flower 3 37 February/April

Fabaceae / Senna sp. candelillo Seed 1 2 February

Malpighiaceae / Byrsonima crassifolia Nanche Seed 3 12 April -May

Malvaceae / Guazuma ulmifolia Caulote Seed 1 8 February

Moraceae / Ficus cotinifolia frutillo Fruit (syconium) 5 39 February-April

Moraceae / Ficus insipida Higo Fruit (syconium) 5 22 May-June

Rubiaceae / Chomelia spinosa Malacahuite Seed 2 9 April

Salicaceae / Homalium trichostemon Palo de piedra Flower 4 22 February/March

Urticaceae / Cecropia obtusifolia Chancarro Fruit 5 7 February, April, May

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. 10, 2023)

feeds as would be expected from the fruiting

abundance index.

DISCUSSION

Food resource availability: Food resource

availability for the OFP demonstrated spatial

fluctuations at the study site. In particular, the

SDF produced greater food resource abundance

in April to June (end dry season). The findings

are consistent with that found by Renton (2001)

in tropical deciduous forest of Jalisco, México,

where there was a greater food abundance for

the Lilac-crowned Amazon (Amazona finschi)

in the SDF during the early to end dry season.

Food resource availability plays an important

role on parrot reproduction (Renton, 2002;

Renton & Salinas-Melgoza, 2004; Rivera et al.,

2020). The OFP breeds in the dry season during

January to June (Collar et al., 2022; De Labra-

Hernández, 2022; Palomera-García, 2010). The

pattern of resource availability demonstrates

the importance of SDF in providing essential

food resources during the OFP breeding season

(raising young period) (Collar et al., 2022).

Also, the DF may be important in providing

food resources at the February to March, when

OFP are egg laying and during hatching period

(De Labra-Hernández, 2022). Conversely, the

SF produced little food resource abundance.

However, the SF could supplement the food

demand that the OFP requires at the end breed-

ing season in April to May. In fragmented

forests, SF provided complementary resources

for parrots species during the breeding season,

as reported for the Northern Mealy Amazon

(Amazona guatemale) (De Labra-Hernández &

Renton, 2019). The information generated in

this study highlights the need to maintain the

complete forest structure in a modified land-

scape to ensure food resources availability for

OFP during the breeding season.

Orange-fronted Parakeet diet: Fruits

(42.3 %) were the most common item eaten by

the OFP, supporting the results by Palomera-

García (2010) in tropical deciduous forest of

Colima, México. In general, smaller-bodied

parrot species consume more fruit (22-44 %) in

the diet, as reported in other psittacine species

Table 2

Food resource availability and use by Eupsittula canicularis, with Bonferroni confidence intervals (95 %), during the middle

to end dry season in three forest types in Santa María Colotepec, Coast of Oaxaca, Mexico.

Vegetation Tree species Available proportion Usage Proportion Bonferroni confidence intervals

DF Ficus cotinifolia 0.07 0.40 0.33 ≤ obs ≤ 0.51*

Gliricidia sepium 0.00 0.30 0.23 ≤ obs ≤ 0.40*

Bursera sp. 0.00 0.07 0.03 ≤ obs ≤ 0.13*

Jacarantia mexicana 0.93 0.05 0.01 ≤ obs ≤ 0.09*

Chomelia spinosa 0.00 0.11 0.06 ≤ obs ≤ 0.18*

Cecropia obtusifolia 0.00 0.07 0.00 ≤ obs ≤ 0.03

SDF Ficus insipida 0.04 0.33 0.25 ≤ obs ≤ 0.41*

Homalium trichostemon 0.59 0.33 0.25 ≤ obs ≤ 0.41*

Bursera simaruba 0.35 0.24 0.16 ≤ obs ≤ 0.31*

Ficus cotinifolia 0.02 0.10 0.05 ≤ obs ≤ 0.16*

SF Mangifera indica 0.00 0.32 0.21 ≤ obs ≤ 0.38*

Gliricidia sepium 0.00 0.13 0.15 ≤ obs ≤ 0.30

Byrsonima crassifolia 0.00 0.23 0.13 ≤ obs ≤ 0.30*

Guazuma ulmifolia 0.94 0.15 0.07 ≤ obs ≤ 0.28*

Senna sp. 0.06 0.13 0.05 ≤ obs ≤ 0.16

Cecropia obtusifolia 0.00 0.04 0.00 ≤ obs ≤ 0.07

DF = tropical deciduous forest, SDF = tropical semi-deciduous forest, and SF = secondary forest. *P < 0.05.

8Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. l0, 2023)

(Galetti, 1997; Hingston et al., 2004; Renton

et al., 2015). Among the species consumed by

the OFP, fruits (syconia) of Ficus insipida and

F. cotinifolia showed a highest feeding records

and OFP consumed this trees species more than

expected from their availability. Ficus has been

reported to be importan in the diet of other

parrots species during the dry season (Matuzak

et al., 2008; Ragusa-Netto, 2002; Ragusa-Net-

to, 2007; Silva & Melo, 2013; Wermundsen,

1997) and for several tropical frugivorous birds

(Bleher et al., 2003). Furthermore, seed of B.

simaruba and flowers of G. sepium, and H.

trichostemon are also usually eaten by the OFP.

Fig. 2. Proportion of use and availability of food resources for Eupsittula canicularis during the middle to end dry season.

A. tropical deciduous forest, B. tropical semi-deciduous forest, C. secondary forest in Santa María Colotepec, Coast of

Oaxaca, Mexico. *P < 0.05.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. 10, 2023)

Fruits such as figs are high in water,

carbohydrates, and calcium, while seeds are

high in protein, minerals, and lipid content

(Gilardi, 1996; Jordano, 2000). In addition,

the flowers contain essential oil, protein, and

carbohydrates (Fonte et al., 2013). In the study

area, the fruits of Ficus, seed of B. simaruba

and flowers of G. sepium, and H. trichostemon

productions play a critical role for providing

nutrients during the OFP breeding season.

The potential loss of these tree species, as a

result of forest degradation, may have conse-

quences in the maintenance of OFP population.

Therefore, the knowledge of principal keystone

trees for the OFP diet is essential for the for-

ests management decisions, especially in a

modified landscape.

Foraging strategies of the Orange-front-

ed parakeet: The OFP respond to spatial

fluctuations in food availability, showing flex-

ibility in the items consumed among forest

types. The OFP had a narrower dietary niche

in the DF and SDF, while dietary niche is

broad in the SF. These results suggest that the

OFP has preferences for some resources in

primary forests, while in SF, the resources are

consumed equally. Similar results have been

observed in other psittacine species that can

adjust their dietary niche based on abundant

resources between habitats (Botero-Delgadillo

et al., 2010; Boyes & Perrin, 2010; Matuzak et

al., 2008; Renton, 2001). In addition, the OFP

selects resources during the breeding season

(narrow Hurlbert index), similarly to reported

for the Ouvea Island Parakeet Eunymphicus

uvaeensis and the Military Macaw A. militaris

(Contreras-González et al., 2009; Robinet et

al., 2003). These results show that the OFP can

modify its foraging strategies by following the

food resources available throughout the dry

season, consuming certain plant species at the

beginning of the breeding season, and includ-

ing other species at the end. This foraging

pattern has been reported in other species of

psittacines of the genus Eupsittula and Arat-

inga (Barros & Marcondes-Machado, 2000;

Paranhos et al., 2009; Silva & Melo, 2013;

Wermundsen, 1997).

The OFP foraged more frequently in

primary forest (DF and SDF) where more

resources are available, compared to the SF

where the lowest number of feedings parakeets

was recorded. These results indicate that the

spatial variation in food availability determine

foraging strategies and influences habitat use

by the OFP inhabit in modified landscape of

the Central Pacific, Mexico. Habitat use pat-

terns by the Lilac-crowned Amazon A. finschi

are determined by spatial heterogeneity in the

availability of food resources (Renton, 2001).

Plasticity in food resources use could be advan-

tageous for psittacine that inhabit in modified

landscape, where the resources availability is

localized in patches of vegetation (Clark &

Mangel, 1984).

The present study demonstrates a flexibil-

ity in OFP diet according to spatial variations

in availability of food resources. The fruits of

Ficus species, seed of B. simaruba and flow-

ers of G. sepium, and H. trichostemon could

be key resources for OFP during the breeding

season. In modified landscape of the Central

Pacific, Mexico, it is necessary to maintain

the complete forest structure to ensure food

resources availability for OFP. The result from

this study is an advance on the knowledge of

OFP foraging ecology in a modified landscape.

Likewise, the information provided in this

study is essential for to develop conservation

Fig. 3. Proportion of availability (fruiting abundance index)

and use of food resources for Eupsittula canicularis during

the middle to end dry season in Santa María Colotepec,

Coast of Oaxaca, Mexico.

10 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71: e52180, enero-diciembre 2023 (Publicado Jul. l0, 2023)

strategies for OFP populations and habitat

management decisions.

ACKNOWLEGDMENTS

This study was part of an Universidad

del Mar (UMAR) internal project (project

ID = CUP: 21E1902) managed by MADLH.

MADLH thanks UMAR for the logistical sup-

port. The authors thank the authorities of Santa

María Colotepec for allowing them to work

within the municipality, as well as the local

people of the Camalote and Corozalito com-

munities for their support as field guides. In

addition, the authors thank Santiago Sinaca

Colín for the taxonomic identification of the

plant species.

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