Interspecies conflict, precarious reasoning, and the gull problem in the Gulf of Maine.

Contemporary conservation science requires mediating conflicts among nonhuman species, but the grounds for favoring one species over another can be unclear. We examined the premises through which wildlife managers picked sides in an interspecies conflict: seabird conservation in the Gulf of Maine (GOM). Managers in the GOM follow a simple narrative dubbed the gull problem. This narrative assumes Larus gulls are overpopulated and unnatural in the region. In turn, these assumptions make gulls an easy target for culling and lethal control when the birds come into conflict with other seabirds, particularly Sterna terns. Surveying historical, natural historical, and ecological evidence, we found no scientific support for the claim that Larus gulls are overpopulated in the GOM. Claims of overpopulation originated from a historical context in which rising gull populations became a nuisance to humans. Further, we found only limited evidence that anthropogenic subsidies make gulls unnatural in the region, especially when compared with anthropogenic subsidies provided for other seabirds. The risks and consequences of leveraging precarious assumptions include cascading plans to cull additional gull populations, obfuscation of more fundamental environmental threats to seabirds, and the looming paradox of gull conservation-even if one is still inclined to protect terns in the GOM. Our close look at the regional history of a conservation practice thus revealed the importance of not only conservation decisions, but also conservation decision-making.

Conflicto interespecífico, razonamiento precario y el problema de las gaviotas en el Golfo de Maine Resumen La ciencia de la conservación actual requiere mediar conflictos entre las especies no humanas, pero los fundamentos para favorecer a una especie por encima de otra pueden ser poco claros. Analizamos las premisas mediante las cuales los gestores de fauna eligen bandos en un conflicto interespecífico: la conservación de aves marinas en el Golfo de Maine (GDM). Los gestores en el GDM siguen una narrativa simple llamada el problema de las gaviotas. Esta narrativa asume que las gaviotas del género Larus no son nativas y tienen una sobrepoblación en la región. En cambio, estas suposiciones hacen que las gaviotas sean un objetivo fácil para el sacrificio y el control letal cuando las aves entran en conflicto con otras aves marinas, en particular con los charranes del género Sterna. Censamos la evidencia histórica, ecológica y de historia natural y no encontramos respaldo científico alguno para la afirmación de que hay una sobrepoblación de gaviotas Larus en el GDM. Esta afirmación se originó a partir de un contexto histórico en el que el incremento poblacional de las gaviotas se volvió una molestia para los humanos. Además, encontramos evidencia limitada de que los subsidios antropogénicos hacen que las gaviotas no sean nativas en la región, en especial cuando los comparamos con los subsidios antropogénicos proporcionados a otras aves marinas. Los riesgos y consecuencias de impulsar suposiciones precarias incluyen los planes en cascada para sacrificar poblaciones adicionales de gaviotas, la ofuscación de amenazas ambientales más fundamentales para las aves marinas y la paradoja inminente de la conservación de las gaviotas­incluso si todavía se inclinan por proteger a los charranes en el GDM. Esta mirada detallada de la historia regional de una práctica de conservación nos reveló la importancia no sólo de las decisiones de conservación, sino también de la toma de decisiones de conservación.

Limited Outbreak of Highly Pathogenic Influenza A(H5N1) in Herring Gull Colony, Canada, 2022.

In summer 2022, highly pathogenic influenza A(H5N1) virus reached the herring gull (Larus argentatus subspecies smithsonianus) breeding colony on Kent Island, New Brunswick, Canada. Real-time monitoring revealed a self-limiting outbreak with low mortality. Proactive seabird surveillance is crucial for monitoring such limited outbreaks, protecting seabirds, and tracing zoonotic transmission routes.

Female and male Leach's Storm Petrels (Hydrobates leucorhous) pursue different foraging strategies during the incubation period.

Reproduction in procellariiform birds is characterized by a single egg clutch, slow development, a long breeding season and obligate biparental care. Female Leach's Storm Petrels Hydrobates leucorhous, nearly monomorphic members of this order, produce eggs that are between 20 and 25% of adult body weight. We tested whether female foraging behaviour differs from male foraging behaviour during the ~ 44-day incubation period across seven breeding colonies in the Northwest Atlantic. Over six breeding seasons, we used a combination of Global Positioning System and Global Location Sensor devices to measure characteristics of individual foraging trips during the incubation period. Females travelled significantly greater distances and went farther from the breeding colony than did males on individual foraging trips. For both sexes, the longer the foraging trip, the greater the distance. Independent of trip duration, females travelled farther, and spent a greater proportion of their foraging trips prospecting widely as defined by behavioural categories derived from a Hidden Markov Model. For both sexes, trip duration decreased with date. Sex differences in these foraging metrics were apparently not a consequence of morphological differences or spatial segregation. Our data are consistent with the idea that female foraging strategies differed from male foraging strategies during incubation in ways that would be expected if females were still compensating for egg formation.

Genomic and phenotypic divergence informs translocation strategies for an endangered freshwater fish.

Translocation, the movement of organisms for conservation purposes, can result in unintended introgression if genetic material flows between populations in new ways. The Bluemask Darter Etheostoma akatulo is a federally endangered species of freshwater fish inhabiting the Caney Fork River system and three of its tributaries (Collins River, Rocky River, and Cane Creek) in Tennessee. The current conservation strategy for Bluemask Darters involves translocating the progeny of broodstock from the Collins River (in the west) to the Calfkiller River (in the east) where the species had been extirpated. In this study, we use ddRAD sequence data from across the extant range to assess this translocation strategy in light of population structure, phylogeny, and demography. We also include museum specimen data to assess morphological variation among extant and extirpated populations. Our analyses reveal substantial genetic and phenotypic disparities between a western population in the Collins River and an eastern population encompassing the Rocky River, Cane Creek, and upper Caney Fork, the two of which shared common ancestry more than 100,000 years ago. Furthermore, morphological analyses classify 12 of 13 Calfkiller River specimens with phenotypes consistent with the eastern population. These results suggest that current translocations perturb the evolutionary boundaries between two delimited populations. Instead, we suggest that repopulating the Calfkiller River using juveniles from the Rocky River could balance conflicting signatures of demography, diversity, and divergence. Beyond conservation, the microgeographic structure of Bluemask Darter populations adds another puzzle to the phylogeography of the hyperdiverse freshwater fishes in eastern North America.

SOCIAL CONTEXT AND THE EVOLUTION OF DELAYED REPRODUCTION IN BIRDS.

Classic life history theory makes generalized predictions about phenotypic correlations across large clades. Modern comparative tests of these correlations account for the underlying structure of phylogenetic trees. Yet neither life history theory nor phylogenetic comparative methods automatically specify how biological mechanisms generate correlations. This problem is evident in comparative analyses of birds. Birds show a correlation between body size and age at first reproduction, but do not actually grow larger if they delay reproduction. Instead, field studies raise the hypothesis that social contexts-especially cooperative breeding, coloniality, and lekking-generate unique demands for behavioral development, which in turn result in delayed reproduction. Here, we support that hypothesis with a comparative dataset spanning 961 species in 155 avian families. Continuous (Ornstein-Uhlenbeck), discrete (hidden state Markov), and phylogenetic regression models revealed delayed reproduction in colonial birds, a weaker signal in cooperative birds, and the consistent evolution of sexual bimaturism in polygynous, lekking birds. These results show an association between diverse social contexts, sex-specific developmental demands, and life history evolution in birds. Considering this diversity, we discuss how even statistically powerful phylogenetic correlations-whether focused on mass, lifespan, or broad social categories-can ultimately fail to model the history of life history evolution.

Constraint and Function in the Predefinitive Plumages of Manakins (Aves: Pipridae).

Birds with delayed plumage maturation exhibit a drab predefinitive plumage, often despite gonad maturation, before developing the definitive plumage associated with increased reproductive success. Manakins are a diverse clade of neotropical lekking birds with extreme sexual dichromatism, radical sexual displays, and a unique diversity in the predefinitive plumages of males across species. Here, we provide the first full review of the natural history of manakin predefinitive plumages as the basis for qualitatively addressing the six major hypotheses about the production and function of predefinitive plumages. We find little evidence to support the possibilities that manakin predefinitive plumages are directly constrained by inflexible molt schedules, resource limitations to definitive coloration, or hormonal ties to reproductive behaviors. There is little evidence that could support a crypsis function, although direct experimentation is needed, and mimicry is refuted except for one unusual species in which predefinitive males sire young. Instead, evidence from a handful of well-studied species suggests that predefinitive plumages help young males explicitly signal their social status, and thereby gain entry to the social hierarchies which dictate future reproductive success. Our conclusions are especially influenced by the unique fact that males of at least 11 species throughout the family exhibit multiple predefinitive plumage stages with distinctively male patches. For each hypothesis, we highlight ways in which a better knowledge of female and young male birds offers critical opportunities for the use of manakins as a model clade.