Apparent Absence of Avian Malaria and Malaria-Like Parasites in Northern Blue-Footed Boobies Breeding On Isla Isabel

Haemosporidian parasites are common in birds, but often are not in seabirds. The absence of vectors/genetic resistance to infection have been proposed to explain this pattern. Examination of different host populations is required to confirm the absence of blood parasites in widespread host species, which could be differently exposed to blood parasites across their geographic range. Moreover, screening of blood parasites in many seabirds has been done only by visual inspection of blood smears, which can miss low-intensity infections. Screening of blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon, combining inspection of blood smears and PCR-based detection methods, revealed that a highly philopatric colony of blue-footed boobies (Sula nebouxii) in the Tropical North Pacific is likely free of these parasites. Earlier detection of Haemoproteus parasites in frigatebirds cohabiting with boobies in our study site and blue-footed boobies breeding on the Galapagos Islands suggests that absence of blood parasites in this northern booby colony could not be attributable to the absence of vectors or genetic resistance to infection. High host specificity or fine-scale spatial heterogeneity in the abundance of insect vectors could explain our negative results, but these hypotheses remain to be tested. We emphasize the relevance of assessing the occurrence of blood parasites in different populations of widespread host species, such as blue-footed boobies.

Telomere lengths correlate with fitness but assortative mating by telomeres confers no benefit to fledgling recruitment

Assortative mating by telomere lengths has been observed in several bird species, and in some cases may increase fitness of individuals. Here we examined the relationship between telomere lengths of Blue-footed Booby (Sula nebouxii) mates, long-lived colonial seabirds with high annual divorce rates. We tested the hypothesis that interactions between maternal and paternal telomere lengths affect offspring and parental survival. We found that relative telomere lengths (RTL) were strongly positively correlated between members of a breeding pair. In addition, RTL of both parents interacted to predict fledgling recruitment, although fledglings with two very long-RTL parents performed only averagely. Telomere lengths also predicted adult survival: birds with long telomeres were more likely to survive, but birds whose mate had long telomeres were less likely to survive. Thus, having long telomeres benefits survival, while choosing a mate with long telomeres benefits reproductive output while penalizing survival. These patterns demonstrate that while a breeder's RTL predicts offspring quality, assortative mating by RTL does not enhance fitness, and a trade-off between different components of fitness may govern patterns of assortative mating by telomere length. They also illustrate how testing the adaptive value of only one parent’s telomere length on either survival or reproductive success alone may provide equivocal results.

Variación poblacional de tres especies de piqueros (Suliformes: Sulidae) en isla Gorgona, Pacífico colombiano, según la temperatura del mar

Introducción: La alteración de la temperatura del ambiente pelágico puede repercutir en la variación poblacional de los consumidores tope como las aves marinas. Objetivo: Evaluar la respuesta poblacional de tres especies de piqueros en isla Gorgona (Pacífico colombiano) con respecto a la variabilidad local y regional de las condiciones de temperatura superficial del mar (TSM). Métodos: Se analizaron las tendencias mensuales de la abundancia de Sula leucogaster, Sula nebouxii y Sula variegata en relación a la variación de la TSM en el área de influencia de Gorgona, la región de San José en la costa del Perú y la región Niño 1+2. Resultados: La mayor correlación positiva se presentó entre S. nebouxii y S. variegata con la TSM de la región Niño 1+2, con un desfase de cuatro y cinco meses, respectivamente. Este desfase temporal posiblemente corresponde al tiempo que demora su migración entre la costa peruana y Gorgona. En contraste, la abundancia de S. leucogaster disminuyó al aumentar la TSM mensual de Gorgona. Conclusiones: Es probable que las tendencias descritas estén relacionadas con la disminución de la productividad y disponibilidad de presas asociadas con temperaturas más cálidas en estas áreas. Se sugiere que la TSM puede influir sobre las tendencias de abundancia de los tres piqueros, y su continuo monitoreo permitirá mejorar el conocimiento sobre la variación natural de estas poblaciones.

Mate selection based on labile traits affects short-term fitness in a long-lived seabird

In long-lived monogamous social species, partner compatibility can play a crucial role in reproductive success. We evaluated assortative mating based on body condition (plasma triglyceride concentration), diet (δ 15 N), and foraging habitat (δ 13 C) in the blue-footed booby Sula nebouxii , a long-lived monogamous seabird. We investigated the effects of assortative mating (sum of triglycerides in a pair) and asymmetry within pairs (residuals from regression of female–male triglycerides) on reproductive performance and offspring growth (alkaline phosphatase, ALP). We found that strong assortative mating determined by body condition and diet seemed to be related to a signalling mechanism (nutritional state). This mating pattern had a substantial effect on the breeding parameters and influenced offspring ALP. Within-pair asymmetry did not influence any reproductive parameters, but the ALP of offspring was related to the within-pair relative female condition. Overall, our results indicate that individuals seek the best possible match to maximize their breeding investment and/or individuals are limited in their mate options by their current body condition, which has consequences for offspring fitness in the short term. Our findings show that assortative mating based on body condition produces notable variation in the joint condition of the pair, which determines their breeding success.

Registro del Piquero Pardo Sula leucogaster en el Refugio de Vida Silvestre Isla Santa Clara, Ecuador

Reportamos un nuevo registro de distribución de Piquero Pardo Sula leucogaster (Sulidae) en el Refugio de Vida Silvestre de la Isla de Santa Clara, en el Golfo de Guayaquil, 43 km de Puerto Bolívar, Machala, provincia de El Oro. Fue observado en un período de 10 días entre el 7 al 17 de julio de 2016, cerca del centro de interpretación ambiental de la isla. Se observó un macho cerca de un grupo de piqueros de patiazul (Sula nebouxii), pero que lo desplazaron a otra zona de isla. No existen reportes previos publicados de esta especie en la parte suroccidental del Ecuador.

Experiencing El Niño conditions during early life reduces recruiting probabilities but not adult survival

In wild long-lived animals, analysis of impacts of stressful natal conditions on adult performance has rarely embraced the entire age span, and the possibility that costs are expressed late in life has seldom been examined. Using 26 years of data from 8541 fledglings and 1310 adults of the blue-footed booby ( Sula nebouxii ), a marine bird that can live up to 23 years, we tested whether experiencing the warm waters and food scarcity associated with El Niño in the natal year reduces recruitment or survival over the adult lifetime. Warm water in the natal year reduced the probability of recruiting; each additional degree (°C) of water temperature meant a reduction of roughly 50% in fledglings' probability of returning to the natal colony as breeders. Warm water in the current year impacted adult survival, with greater effect at the oldest ages than during early adulthood. However, warm water in the natal year did not affect survival at any age over the adult lifespan. A previous study showed that early recruitment and widely spaced breeding allow boobies that experience warm waters in the natal year to achieve normal fledgling production over the first 10 years; our results now show that this reproductive effort incurs no survival penalty, not even late in life. This pattern is additional evidence of buffering against stressful natal conditions via life-history adjustments.