Why do avian responses to change in Arctic green-up vary?

Global climate change has altered the timing of seasonal events (i.e., phenology) for a diverse range of biota. Within and among species, however, the degree to which alterations in phenology match climate variability differ substantially. To better understand factors driving these differences, we evaluated variation in timing of nesting of eight Arctic-breeding shorebird species at 18 sites over a 23-year period. We used the Normalized Difference Vegetation Index as a proxy to determine the start of spring (SOS) growing season and quantified relationships between SOS and nest initiation dates as a measure of phenological responsiveness. Among species, we tested four life history traits (migration distance, seasonal timing of breeding, female body mass, expected female reproductive effort) as species-level predictors of responsiveness. For one species (Semipalmated Sandpiper), we also evaluated whether responsiveness varied across sites. Although no species in our study completely tracked annual variation in SOS, phenological responses were strongest for Western Sandpipers, Pectoral Sandpipers, and Red Phalaropes. Migration distance was the strongest additional predictor of responsiveness, with longer-distance migrant species generally tracking variation in SOS more closely than species that migrate shorter distances. Semipalmated Sandpipers are a widely distributed species, but adjustments in timing of nesting relative to variability in SOS did not vary across sites, suggesting that different breeding populations of this species were equally responsive to climate cues despite differing migration strategies. Our results unexpectedly show that long-distance migrants are more sensitive to local environmental conditions, which may help them to adapt to ongoing changes in climate.

Oversummering juvenile and adult Semipalmated sandpipers in Perú gain enough survival to compensate for foregone breeding opportunity.

BACKGROUND: Age at maturity and the timing of first breeding are important life history traits. Most small shorebird species mature and breed as 'yearlings', but have lower reproductive success than adults. In some species, yearlings may defer northward migration and remain in non-breeding regions ('oversummering') until they reach 2 years of age. Some adults also oversummer. Oversummering would be favoured by natural selection if survival were as a result raised sufficiently to compensate for the missed breeding opportunity. Several thousand Semipalmated Sandpipers (Calidris pusilla) spend the non-breeding period at Paracas, Perú, including individuals with long bills (likely from eastern Arctic breeding populations ~ 8000 km distant) and short bills (likely from western Arctic breeding populations, up to 11,000 km distant), with short-billed birds more likely to oversummer. We tested the prediction that oversummering birds have higher survival than migrants, and that the magnitude of this higher survival for oversummering birds is enough to compensate for their lost breeding season. METHODS: We used a Multi-State Mark-Recapture model based on 5 years of encounter data (n = 1963 marked birds, and 3229 resightings) obtained year-round at Paracas, Perú, to estimate seasonal (i.e. breeding and non-breeding) survivorship for migrant and oversummering birds. We calculated the magnitude of the oversummering survival advantage required to compensate, for both yearlings and adults, based on published measures of annual survival and reproductive success. Using bill length as a proxy for migration distance, we investigated whether migratory survival is distance-dependent. RESULTS: We estimate that 28% of yearlings and 19% of adults oversummer. Survival is higher for oversummering birds than for migrants, and the oversummering survival advantage is greater for adults (0.215) than for yearlings (0.140). The theoretical thresholds predicted by the size of the missed reproductive opportunity are 0.240 for adults and 0.134 for yearlings. Migratory survival decreases and the oversummering rate increases with migration distance, as assessed by culmen length. CONCLUSIONS: Our results support the life history hypothesis that oversummering raises survival enough to compensate for the loss of a breeding opportunity. Greater migration distance lowers survival and increases the probability of oversummering.

Sobre la importancia de la certificación internacional para los anilladores de aves en Perú / About international certification importance for Bird Banders in Peru

La certificación como anillador de aves consiste en validar el nivel de conocimiento y experiencia de personas frente a un estándar consolidado de trabajo en el ejercicio de la captura, anillado, manejo, y liberación de aves, con el fin de promover la seguridad del ave, la seguridad del anillador y la calidad de los datos colectados. El Consejo Norteamericano de Anillado (NABC) es una organización sin fines de lucro, engloba a diversas organizaciones de investigación, conservación y gestión de la avifauna en Norteamérica. Continuando con su principal misión de promover prácticas responsables de la técnica del anillado de aves bajo criterios estandarizados y éticos, en un trabajo conjunto con el Centro de Ornitología y Biodiversidad (CORBIDI) y otras instituciones afines, entre el 2017 y el 2018 se han desarrollado las tres primeras sesiones de certificación NABC en el Perú. El presente trabajo intenta responder algunas de las preguntas más frecuentes relacionados con estas sesiones de certificación, así como los esfuerzos del anillado de aves promovidos por el Programa de Anillamiento CORBIDI (PAC).

Certification as bird bander implies to validate the level of knowledge and experience of people with regard to a consolidated standard of work in the exercise of capture, banding, handling, and release of birds, in order to promote the safety of the bird, the security of the bander and the quality of the data collected. The North American Banding Council (NABC) is a non-profit organization that includes diverse organizations of research, conservation and management of North American avifauna. Continuing with its mission to promote responsible bird-banding practices under standardized and ethical criteria, in a joint effort with the Centro de Ornitologia y Biodiversidad (CORBIDI) and other related institutions, the first three NABC certification sessions were recently held in Peru. This work tries to answer some of the most frequent questions related to these certification events and the bird banding efforts promoted by the Programa de Anillamiento CORBIDI (PAC).