Cannibalism occurs regularly across a broad range of taxa with a variety of ecological and evolutionary consequences. Rises in sea surface temperature (SST) have been linked to increased cannibalism in some species, including polar bears (Ursus maritimus), Peruvian anchovy (Engraulis ringens), and Peruvian hake (Merluccius gayi peruanus), and might be expected in birds that depend on marine food webs for sustenance. Increased SSTs are associated with lowered ocean thermoclines and weakened upwellings. These changes, in turn, lead to decreased productivity in surface water and movement of surviving forage fish to deeper water, thereby food-stressing surface feeders such as gulls, diminishing energy intake and lengthening foraging bouts. While controlling for a suite of other environmental factors, we tested whether egg cannibalism and hatching success were independent of rises in local SST at a colony of Glaucous-winged Gulls (Larus glaucescens) and Glaucous-winged 3 Western Gull (L. glaucescens 3 occidentalis) hybrids during 2006-2011 on Protection Island, Washington, USA. Cannibalism increased and hatching success decreased with rises in SST. It is unclear if rises in SST impact overall population trends. Gulls are multiyear breeders; if they experience reproductive failure during one or several El Niño-Southern Oscillation-related events, they typically have other opportunities to breed. With rising SSTs associated with climate change, however, increasing levels of cannibalism could lead to declining populations in the absence of compensatory adaptive modifications or range shifts.El canibalismo de huevos en colonias de gaviotas aumenta con la temperatura superficial del mar RESUMEN Q 2014 Cooper Ornithological Society.

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Glaucous-winged gulls Larus glaucescens and western gulls L. occidentalis hybridize extensively where their ranges overlap along the coasts of Washington and Oregon, producing a continuum of phenotypic intergrades between the two parental species. Th is zone often is considered an example of geographically bounded hybrid superiority, but studies of relative success among parental types and hybrids have not provided consistent support for this model. We tested the predictions of the dynamic-equilibrium and geographically bounded hybrid superiority hypotheses by studying mate choice and reproductive success among gulls on Protection Island, Washington, the largest breeding colony of glaucous-winged/western gulls within the hybrid zone. Th e dynamic-equilibrium hypothesis posits that hybridization due to dispersal balances selection against less fi t hybrids and assortative mating is adaptive. Geographically bounded hybrid superiority posits that hybrids are better fi t than parental types within an ecotone between the environments to which the parental species are adapted, and a preference for hybrid mates is adaptive. Additionally, we investigated whether hatching success and nest site choice are correlated for Protection Island gulls. We assigned a hybrid index to each sample bird by examining plumage melanism and bare part coloration in the fi eld. Sheltered nests contained larger clutches and exhibited increased hatching success, but choice of nest habitat was not associated with hybrid index. Western gull-like pairs produced smaller third eggs; however, hybrid index was not correlated with clutch size or hatching success. Protection Island gulls did exhibit assortative mating. In short, we did not fi nd strong support for either geographically bounded hybrid superiority or the dynamic-equilibrium hypothesis.

Some phylogenetic problems remain unresolved even when large amounts of sequence data are analyzed and methods that accommodate processes such as incomplete lineage sorting are employed. In addition to investigating biological sources of phylogenetic incongruence, it is also important to reduce noise in the phylogenomic dataset by using appropriate filtering approach that addresses gene tree estimation errors. We present the results of a case study in manakins, focusing on the very difficult clade comprising the genera Antilophia and Chiroxiphia. Previous studies suggest that Antilophia is nested within Chiroxiphia, though relationships among Antilophia+Chiroxiphia species have been highly unstable. We extracted more than 11,000 loci (ultra-conserved elements and introns) from whole genomes and conducted analyses using concatenation and multi-species coalescent methods. Topologies resulting from analyses using all loci differed depending on the data type and analytical method, with two clades (Antilophia+Chiroxiphia and Manacus+Pipra+Machaeopterus) in the manakin tree showing incongruent results. We hypothesized that gene trees that conflicted with a long coalescent branch (e.g., the branch uniting Antilophia+Chiroxiphia) might be enriched for cases of gene tree estimation error, so we conducted analyses that either constrained those gene trees to include monophyly of Antilophia+Chiroxiphia or excluded these loci. While constraining trees reduced some incongruence, excluding the trees led to completely congruent species trees, regardless of the data type or model of sequence evolution used. We found that a suite of gene metrics (most importantly the number of informative sites and likelihood of intralocus recombination) collectively explained the loci that resulted in non-monophyly of Antilophia+Chiroxiphia. We also found evidence for introgression that may have contributed to the discordant topologies we observe in Antilophia+Chiroxiphia and led to deviations from expectations given the multi-species coalescent model. Our study highlights the importance of identifying factors that can obscure phylogenetic signal when dealing with recalcitrant phylogenetic problems, such as gene tree estimation error, incomplete lineage sorting and reticulation events.