Diet and feeding selectivity of the Andean Flamingo Phoenicoparrus andinus and Chilean Flamingo Phoenicopterus chilensis in lowland wintering areas

POLLA W.; DI PASQUALE V.; RASUK M.C.; BARBERIS I.; MANZO R.; PAGGI J.C.; FARÍAS M.E.; CONTRERAS M.; DEVERCELLI M.

Wildfowl

Wildfowl

Año: 2019

0954-6324

Flamingos Phoenicopteridae sp. are gregarious birds that travel long distances betweenbreeding and feeding sites. Here we describe the diet and feeding selectivity oftwo flamingo species, the Andean Flamingo Phoenicoparrus andinus and ChileanFlamingo Phoenicopterus chilensis, which coexist in a lowland area of Argentina.Environmental characteristics and available food resources were assessed at twelvelakes where feeding flocks of both species of flamingos occurred. Food items found in faeces (16S rRNA for bacteria and archaea) and microscopic analyses (for Cyanobacteria, microalgae and microinvertebrates) were analysed, and the birds? feeding selectivity and niche overlap were estimated. Results showed that the lakeswere of eutrophic to hypereutrophic status, and with hypohaline to mesohalinesalinity levels. Predominant microorganisms belonged to the Planctomycetes,Verrucomicrobia, Chloroflexi, Euryarchaeota, Cyanobacteria, Bacillariophytaand Copepoda phyla. Euryarchaeota and Firmicutes were the main phyla foundin the faeces, with Chloroflexi and Planctomycetes also present in smallerquantities. Proteobacteria were well represented in Andean Flamingo faeces, butVerrucomicrobia were scarce in both species. Cyanobacteria, Bacillariophyta,Copepoda, Cladocera, and Rotifera were abundant in Chilean Flamingo faeces, andlarger organisms belonging to Ostracoda, Nematoda, and Diptera were also found.The most consumed taxa were in the intermediate to large size range (104 to 2×105μm3, and 108 to 2×108 μm3). Andean Flamingo faeces were composed mainly ofmicroalgae, especially diatoms. Cladocera and Copepoda species were found to alesser extent, showing the flamingos? preference for intermediate prey sizes (104 to2×105 μm3). Food selection was probably dependent on the spatial variability in preyavailability, as both positive selectivity (for Bacillariophyceae) and avoidance (forCopepoda) were observed in Chilean Flamingos. In contrast, Andean Flamingosshowed a high positive selection for diatoms, and strong negative selection formicroinvertebrates. Both flamingo species can apparently coexist whilst feeding on awide spectrum of microorganisms, but trophic niches differed in the amounts ofCyanobacteria, microalgae and microinvertebrates taken. Such a low niche overlapprobably contributes to the coexistence of both sympatric species in similar waters.