scholarly journals Optimal diet strategy of a large-bodied psittacine: food resource abundance and nutritional content enable facultative dietary specialization by the Military Macaw

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Sylvia Margarita de la Parra-Martínez ◽  
Luis Guillermo Muñoz-Lacy ◽  
Alejandro Salinas-Melgoza ◽  
Katherine Renton

Abstract Background Dietary specialization should arise when there is a relatively high abundance of a particular resource, where animals may select food items to obtain an optimal diet that maximizes energy intake. Large-bodied psittacines frequently exhibit a narrow dietary niche with specific habitat use, but few studies have determined whether psittacines select food resources, and how this influences habitat use. Methods We established fruiting phenology transects to evaluate food resource availability for the large-bodied Military Macaw (Ara militaris) in semi-deciduous, deciduous, and pine-oak forest at two sites along the coast of Jalisco, during the dry season when macaws are nesting. We also determined Military Macaw diet by observations of foraging macaws along transect routes, and conducted bromatological analysis of the nutritional content of the most consumed resource. Results Military Macaws used six plant species as food items during the dry season, and had a narrow dietary niche (Levins’ B = 0.28), with 56% of foraging macaws consuming the seeds of Hura polyandra. No food resources were recorded in pine-oak forest during the dry season, with food resources and foraging by macaws concentrated in tropical deciduous and semi-deciduous forest, where H. polyandra was the most abundant fruiting tree species. When considering the proportional availability of food resources, we determined a broad Hurlbert dietary niche breadth of H = 0.67, indicating that Military Macaws consumed food resources according to their availability. Furthermore, the seeds of H. polyandra were an important source of protein, carbohydrates, minerals and moisture, and the hard fruit-casing means that these seeds are exclusively available for macaws. Conclusions By concentrating their diet on the most abundant resources, Military Macaws may increase foraging efficiency in the dry season. The high nutrient content also means that concentrating the diet on seeds of H. polyandra may be an optimal foraging strategy for Military Macaws to meet their energy requirements during the breeding season.

2008 ◽  
Vol 6 (4) ◽  
pp. 567-576 ◽  
Author(s):  
Gisele Caroline Novakowski ◽  
Norma Segatti Hahn ◽  
Rosemara Fugi

We assessed the trophic structure of the fish fauna in Sinhá Mariana pond, Mato Grosso State, from March 2000 to February 2001. The aim was to determine the feeding patterns of the fish species during the rainy and dry seasons. The diets of 26 species (1,294 stomach contents) were determined by the volumetric method. Insects and fish were the most important food resources: insects were the dominant food of 23% and 27% of the species, respectively, in the rainy and dry season, and fish was the dominant item for 31% of the species in both seasons. Cluster analysis (Euclidean Distance) identified seven trophic guilds in the rainy season (detritivores, herbivores, insectivores, lepidophages, omnivores, piscivores and planktivores), and five trophic guilds in the dry season (detritivores, insectivores, lepidophages, omnivores and piscivores). The smallest mean values of diet breadth were observed for the specialist guilds (detritivores, lepidophages and piscivores), in both seasons. The widest means for diet breadth were observed for the omnivores, regardless of the season. In general, there was no seasonal variation in feeding overlap among the species studied. At the community level, diet overlap values between species were low (< 0.4) for 80% of the pairs in each season, suggesting wide partitioning of the food resource. The fish assemblage showed a tendency toward trophic specialization, regardless of the season, although several species changed their diets. We might consider two non-excludent hypothesis: that there is no pattern on the use of seasonal food resources and/or probably there are several patterns, because each one is based on characteristics of the studied site and the taxonomic composition of the resident species.


1998 ◽  
Vol 11 (1) ◽  
pp. 25-43 ◽  
Author(s):  
Jon E. L. Day ◽  
Ilias Kyriazakis ◽  
Peter J. Rogers

AbstractThe food choice and intake of animals (including humans) has typically been studied using frameworks of learning and feeding motivation. When used in isolation such frameworks could be criticized because learning paradigms give little consideration to how new food items are included or excluded from an individual's diet, and motivational paradigms do not explain how individuals decide which food to eat when given a choice. Consequently we are posed with the question of whether individuals actively interact with the food items present in their environment to learn about their nutritional properties? The thesis of this review is that individuals aremotivatedto actively sample food items in order to assess whether they are nutritionally beneficial or harmful. We offer a unifying framework, centred upon the concept of exploratory motivation, which is a synthesis of learning and paradigms of feeding motivation. In this framework information gathering occurs on two levels through exploratory behaviour: (i) the discrimination of food from nonfood items, and (ii) the continued monitoring and storage of information concerning the nutritional properties of these food items. We expect that this framework will advance our understanding of the behavioural control of nutrient intake by explaining how new food items are identified in the environment, and how individuals are able to monitor changes in the nutritional content of their food resource.


The Condor ◽  
2001 ◽  
Vol 103 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Katherine Renton

Abstract The pattern of food resource availability and use by Lilac-crowned Parrots (Amazona finschi) was evaluated in tropical dry forest of the Reserva de la Biosfera Chamela-Cuixmala, western Mexico. Monthly fruiting phenology transects were conducted throughout the year in deciduous and semi-deciduous forest to determine temporal and spatial variability in resource abundance. Resource use by parrots was evaluated through observations of diet and habitat use. There was significant temporal and spatial variability in food resource abundance, with semi-deciduous forest providing greater food resources for parrots during the dry season, whereas food resource abundance increased in deciduous forest during the rainy season. The critical period of food resource scarcity occurred during May–June at the end of the long dry season. Lilac-crowned Parrots were pre-dispersal seed predators, and exhibited high flexibility in diet, incorporating dietary switching, as well as niche-breadth contraction and expansion, which corresponded with temporal variations in food resource availability. There was low overlap in parrot diets between seasons, with parrots exhibiting a narrow food niche-breadth during the late dry season when resource availability declined. Parrots also demonstrated spatial variation in habitat use, corresponding to fluctuations in the availability of food resources in different habitats. This flexibility in foraging enables parrots to closely track and exploit seed resources which exhibit high temporal and spatial variability in abundance.


2003 ◽  
Vol 30 (6) ◽  
pp. 593 ◽  
Author(s):  
Simon C. Stirrat

Radio-tagged male and female agile wallabies were tracked in the wet and dry seasons at a site in Darwin, Northern Territory, and home ranges estimated using a kernel-based estimator. Home-range size (95% contour) was larger in the dry season, when food quality was poorer, and males had larger home ranges than females. Core range size (55% contour) did not differ between seasons or sexes. Average male and female home-range sizes in the wet season were 16.6 ha and 11.3 ha respectively. Wet-season core range sizes were 4.8 ha and 3.2 ha respectively. Average male and female home-range sizes in the dry season were 24.6 ha and 15.3 ha respectively, and dry-season core range sizes were 5.1 ha and 4.0 ha respectively. Home-range size for both sexes varied in the two seasons; the smallest and largest female home ranges were 6.3 ha and 24.0 ha respectively, while male home-range size varied from 7.6 ha to 38.2 ha. Seasonal differences in home-range size can be attributed to expansion of night-time foraging areas in the dry season when good-quality food resources were in short supply. Habitat use also differed between seasons. In the dry season more fixes were located in forest areas, particularly in the evening, when wallabies foraged in forest areas for alternate food resources including browse, leaf litter, flowers and fruits of rainforest tree and shrub species. In the wet season, wallabies emerged from day-time resting areas earlier in the afternoon and therefore more wallabies were located in open areas grazing on high-quality herbage in the evening.


2020 ◽  
Vol 15 (3) ◽  
pp. 701-716
Author(s):  
Daisy A. Gómez-Ruiz ◽  
Camilo Sánchez-Giraldo ◽  
Juan L. Parra ◽  
Sergio Solari

Fauna in Tropical Dry Forest (TDF) is highly dependent on water availability due to a marked seasonality in precipitation. There are few studies addressing carnivore’s ecology and the role of seasonality of TDF in Neotropics. We used scent-station and camera trapping to assess seasonal changes in occurrence and habitat use probability with seasonality. We also described activity patterns and collected fresh scats to describe diet for small sized carnivore species in a TDF fragment in the Colombian Caribbean region. We present information regarding: Cerdocyon thous, Leopardus pardalis, and Procyon spp. The analysis showed a significantly higher occurrence probability during the dry season for the three species, and no differences in the detection probability between seasons. The diet of C. thous included 24 different food items; for L. pardalis it was composed of seven items, and finally, 25 food items were identified in the diet of Procyon spp. We found that the three species presented activity patterns corresponding with previous studies. Finally, our results reflect that these species are probably making more/larger habitat use during the dry season than in the wet season, because the area has permanent water ponds by which limited resources (such as water and food) are available almost constantly in this natural reserve.


2007 ◽  
Author(s):  
Sean D. Farley ◽  
Herman Griese ◽  
Rick Sinnott ◽  
Jessica Coltrane ◽  
Chris Garner ◽  
...  

2005 ◽  
Vol 265 (4) ◽  
pp. 377-385 ◽  
Author(s):  
Geir Steinheim ◽  
Per Wegge ◽  
Jo I. Fjellstad ◽  
Shant R. Jnawali ◽  
Robert B. Weladji

2009 ◽  
Vol 59 (2) ◽  
pp. 145-157 ◽  
Author(s):  
Octavio Monroy-Vilchis ◽  
Vicente Urios ◽  
Martha Zarco-González ◽  
Clarita Rodríguez-Soto

AbstractIn this study the habitat use and activity patterns of the two of the largest cats of the Americas in central Mexico were studied. Three ways to detect felid presence were employed from August 2002 to May 2006: interviews, signs, and camera-traps. 478 records were obtained, from which 441 were from cougar and 37 from jaguar. These records included positive response in 118 of 140 interviews and 236 records of signs (mainly tracks and scats), and 124 photographs. Both felids preferred pine-oak forest habitats, with altitudes higher than 1800 m, distances between 3509 and 4377 m from roads, between 2329 and 4650 m from settlements, and distances to very steep slopes between 1048 and 2059 m, for jaguar, and for cougar lower than 1047 m. Jaguar activity was recorded mainly during nighttimes, between 0:00 and 6:00, whereas cougar was active between 4:00 and 6:00 and between 18:00 and 22:00 hours, avoiding the jaguar's principal activity period.


2002 ◽  
Vol 62 (2) ◽  
pp. 339-346 ◽  
Author(s):  
J. RAGUSA-NETTO

Figs are a remarkable food resource to frugivores, mainly in periods of general fruit scarcity. Ficus calyptroceras Miq. (Moraceae) is the only fig species in a type of dry forest in western Brazil. In this study I examined the fruiting pattern as well as fig consumption by birds in F. calyptroceras. Although rainfall was highly seasonal, fruiting was aseasonal, since the monthly proportion of fruiting trees ranged from 4% to 14% (N = 50 trees). I recorded 22 bird species feeding on figs. In the wet season 20 bird species ate figs, while in the dry season 13 did. Parrots were the most important consumers. This group removed 72% and 40% of the figs consumed in the wet and dry seasons, respectively. No bird species increases fig consumption from dry to wet season. However, a group of bird species assumed as seed dispersers largely increases fig consumption from wet to dry season, suggesting the importance of this resource in the period of fruit scarcity. The results of this study points out the remarkable role that F. calyptroceras plays to frugivorous birds, in such a dry forest, since its fruits were widely consumed and were available all year round.


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