Avian prey-dropping behavior. II. American crows and walnuts

Complex and energetically expensive foraging tasks should beshaped by natural selection to be efficient. Many species ofbirds open hard-shelled prey by dropping the prey repeatedlyonto the ground from considerable heights. Urban-dwelling Americancrows (Corvus brachyrhynchos) forage in this way on two speciesof walnuts in central California, USA. As predicted from a theoreticalmodel, crows dropped nuts with harder shells from greater heightsand dropped them from greater heights when over softer substrates.The height selected for dropping nuts decreased in the presenceof numerous nearby conspecifics, indicating that crows weresensitive to the risk of kleptoparasitism when selecting dropheights. Drop height decreased with repeated drops of the samewalnut, suggesting that crows adjusted for the increasing likelihoodthat a repeatedly-dropped nut would break on subsequent drops.Crows did not alter height of drop in accordance with differencesin the mass of the prey. When faced with multiple prey typesand dropping substrates, and high rates of attempted kleptoparasitism,crows adjusted the height from which they dropped nuts in waysthat decreased the likelihood of kleptoparasitism and increasedthe energy obtained from each nut.     

Colonization byCladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

Summary Cladosporium cladosporioides andC. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.     

Captive breeding and rearing of critically endangered Mauritius fodies Foudia rubra for reintroduction

In‐situ captive rearing of endangered passerines for reintroduction has rarely been used as a conservation tool. Nests of Mauritius fodies threatened with predation by introduced mammalian predators were harvested from the wild, and chicks were reared to independence for release onto an offshore, predator‐free island. The daily probability of the survival was higher in captivity than in the wild, and 69 chicks were reared to fledging of which 47 would have been expected to fledge in the wild. Harvesting of nests probably had little impact on the wild population. Captive breeding trials on Mauritius fodies showed that large numbers of individuals could be produced for a release program from a small number of pairs if enough space was provided. Artificial incubation of passerine eggs and rearing of chicks can be used to increase the productivity of endangered taxa. Zoos can play an important role in in‐situ conservation programs through provision of avicultural expertise and training of local staff. Zoo Biol 27:255–268, 2008. © 2008 Wiley‐Liss, Inc.     

Rookery through rehabilitation: Microbial community assembly in newborn harbour seals after maternal separation

Microbial community assembly remains largely unexplored in marine mammals, despite its potential importance for conservation and management. Here, neonatal microbiota assembly was studied in harbour seals (Phoca vitulina richardii) at a rehabilitation facility soon after maternal separation, through weaning, to the time of release back to their native environment. We found that the gingival and rectal communities of rehabilitated harbour seals were distinct from the microbiotas of formula and pool water, and became increasingly diverse and dissimilar over time, ultimately resembling the gingival and rectal communities of local wild harbour seals. Harbour seal microbiota assembly was compared to that of human infants, revealing the rapid emergence of host specificity and evidence of phylosymbiosis even though these harbour seals had been raised by humans. Early life prophylactic antibiotics were associated with changes in the composition of the harbour seal gingival and rectal communities and surprisingly, with transient increases in alpha diversity, perhaps because of microbiota sharing during close cohabitation with other harbour seals. Antibiotic-associated effects dissipated over time. These results suggest that while early life maternal contact may provide seeding for microbial assembly, co-housing of conspecifics during rehabilitation may help neonatal mammals achieve a healthy host-specific microbiota with features of resilience.