Foraging ecology of the globally threatened Nilgiri Wood Pigeon(Columba elphinstonii)in the Western Ghats,India

Foraging ecology of the globally endangered Nilgiri Wood Pigeon(Columba elphinstonii) was investigated in the Western Ghats,India,using faecal sampling and direct observations.The birds fed on fruits of 39 plant species,on seeds of 11 species,flowers and leaf buds of four species and a few ground invertebrates.Direct observations across seasons showed nine plant species were selected more often(47% of observations),with fruits of the members of the family Lauraceae the most preferred.Gleaning accounted for 76% of feeding methods throughout the year.Feeding was mainly from twigs at the edges on the upper and middle canopy(> 6 m).Frequency of feeding on fruits correlated significantly with fruit abundance,which depended on rainfall.The present study indicates that the pigeon requires a wide variety of diets from different forest environments.Conservation of this species depends on preserving all habitat types required to meet their resource needs throughout the year.

Stable seasonal migration patterns in giant pandas

A critical function of animal movement is to maximize access to essential resources in temporally fluctuating and spatially heterogeneous environments.Seasonally mediated resource fluctuations may influence animal movements,enabling them to track changing resource distributions,resulting in annual migration patterns.The conservation-dependent giant panda(Ailuropoda melanoleuca) displays seasonal movement patterns;however,the key factor driving these seasonal migration patterns remains poorly understood.Here,we used GPS tracking collars to monitor the movements of six giant pandas over a 12-year period across different elevations,and performed statistical analysis of seasonal migration directions,routes,habitat revisitation,home range overlap,first arrival events,and stability.Our results revealed a compelling pattern of seasonal migrations that facilitated the ability of the pandas to forage at the appropriate time and place to maximize nutritional intake.Our results indicated that pandas utilize spatial memory to locate reliable food resources,as evidenced by their annual return to the same or similar winter and summer home ranges and the consistently maintained percentage of home range overlap.These novel insights into giant panda foraging and movement ecology not only enhance our understanding of its ability to adapt to nutritionally poor dietary resources but also provide important information for the development of resource utilization-based protection and management strategies.

Intraguild niche partitioning in granivorous birds from the late past

Niche partitioning is a widespread ecological strategy within trophic guilds,ensuring the coexistence of sympatric species by reducing interspecific competition.Stable isotope analysis of carbon and nitrogen and isotopic niche metrics(width and overlap)are used as a proxy to investigate niche partitioning among species of a guild.In our study,we investigated if niche partitioning was an ecological mechanism contributing to the coexistence of granivorous birds from the same geographic region along time,employing an isotopic approach.We sampled and isotopically analyzed(δ^(13)C andδ^(15)N values)wing feathers from 58 specimens of granivorous birds collected between 1900 and 1966 in southeastern Brazil.We grouped birds according to the main habitat type used by them(forest:Cyanoloxia brissonii,Leptotila and Leptotila verreauxi;and grassland:Columbina squammata and Sicalis flaveola).We used the Isotopic Richness(IRic)metric to measure the isotopic niche width and the Isotopic Similarity(ISim)and Isotopic Nestedness(INes)metrics to measure the niche overlap between groups and species.The results of low isotopic niche overlap suggest that common granivorous birds had a clear niche partitioning in southeastern Brazil in the late past,especially through foraging in distinct habitat types(forest and grassland;ISim=0.1,INes=0.2).Niche overlaps in almost all species-by-species comparisons were low(ISim≤0.3,INes≤0.4),except between C.brissonii and L.verreauxi(ISim=0.6,INes=1.0).These results suggest that these birds,belonging to the same trophic guild,coexisted through niche and resource partitioning.Despite being considered a plastic trophic guild,the isotopic niche partitioning among granivorous birds indicates that each of these species uses a set of specific resources and habitats.This raises an ecological concern about the homogenization of landscapes across the Neotropics,oversimplifying food resources and habitats to granivorous birds.