Neither sex appears to benefit from divorce within migratory Northern Flickers consistent with accidental loss and bet-hedging

Divorce is widespread among species of birds and may either be an adaptive strategy to secure a better mate or territory or be a nonadaptive result of a failure to maintain the pairbond. I examined the causes and consequences for divorce in the Northern Flicker (Colaptes auratus), a migratory woodpecker with a high annual mortality rate. In a long-term population study of 1,793 breeding pairs over 17 years, the within-season divorce rate was 4.6% and the between-season divorce rate was 15.5%. Retained pairs within a season initiated their renest 5 days faster than divorced birds that had no greater fledgling production, suggesting that within-season divorce was making the best of a bad job with severe time constraints. Poor performance in the year prior to divorce was not strongly associated with divorce, and analysis of multiple breeding stages revealed that divorcing individuals in the subsequent year had later laying dates, smaller clutches, and fewer fledglings than retained pairs but no better performance than widowed individuals. Analyzing the data separately by sex showed that neither males nor females benefitted from divorce. Thus, there is a reproductive cost linked to finding a new partner per se, but no reproductive advantage associated with divorce. New mates after divorce were usually not older (not higher quality) than previous mates, so intrasexual competition was probably not driving partnership splits. The most plausible explanation seems to be a “bet-hedging” hypothesis in which birds re-pair rapidly in spring if their previous mate does not quickly arrive during spring migration. Divorce in Northern Flickers does not appear to be adaptive and future studies on arrival and interactions of individuals in spring will elucidate proximate constraints on relocating the previous partner.

Migratory Seasonality and Phenology by Birds in a Temperate Forest with Two Disturbance Conditions

Objective: The objective was to infer the effect of the variables phenology (migration-non-migration), seasonal (rainfall-dry season), sex and forest condition on the abundances of birds (resident-migratory) in a semi-preserved and disturbed oak pine forest. Design/methodology/approach: It was carried out in Monte Tlaloc, State of Mexico, under two conditions of apparent disturbance, semi-preserved oak pine forest and disturbed oak pine forest. Ten bird samplings were carried out with "count on point" with a fixed radius of 25 m, covering the 4 seasons of the year and migratory periods. With the previous data, the Relative Abundance Index (RAI) was estimated. To infer the effect of the variables phenology, seasonality, sex and forest condition on the abundances of birds, generalized linear models were elaborated. Results: The IAR of the birds registered in the semi-considered pine forest indicates that the species with the lowest presence was Aphelocoma ultramarina (0.002) and with the highest frequency Empidonax sp. (0.13), unlike to that found in the disturbed pine forest where the lowest IAR corresponded to Colaptes auratus (0.003) and with the highest appearance was Ptiliogonys cinereus (0.23). The Generalized Linear Model suggested that forest condition and phenology are significantly related to the frequency of species. Limitations on study/implications: In this study it was found that the abundance of birds was affected by the condition of the forest and that the phenology (migration-non-migration), seasonal (rain-dry season), sex and condition of the forest were related to the abundance of birds. Four species classified as under Special Protection and two Threatened according to NOM-059 were registered as well as the presence of four endemic species which highlights the importance of conserving these ecosystems. Findings/conclusions: The fauna communities present in Monte Tláloc highlight the importance of conserving the pine-oak forests since this site is part of the Eje Neovolcanico Transversal.

De novo assembly of a chromosome-scale reference genome for the northern flicker Colaptes auratus

The northern flicker, Colaptes auratus, is a widely distributed North American woodpecker and a long-standing focal species for the study of ecology, behavior, phenotypic differentiation, and hybridization. We present here a highly contiguous de novo genome assembly of C. auratus, the first such assembly for the species and the first published chromosome-level assembly for woodpeckers (Picidae). The assembly was generated using a combination of short-read Chromium 10× and long-read PacBio sequencing, and further scaffolded with chromatin conformation capture (Hi-C) reads. The resulting genome assembly is 1.378 Gb in size, with a scaffold N50 of 11 and a scaffold L50 of 43.948 Mb. This assembly contains 87.4–91.7% of genes present across four sets of universal single-copy orthologs found in tetrapods and birds. We annotated the assembly both for genes and repetitive content, identifying 18,745 genes and a prevalence of ∼28.0% repetitive elements. Lastly, we used fourfold degenerate sites from neutrally evolving genes to estimate a mutation rate for C. auratus, which we estimated to be 4.007 × 10−9 substitutions/site/year, about 1.5× times faster than an earlier mutation rate estimate of the family. The highly contiguous assembly and annotations we report will serve as a resource for future studies on the genomics of C. auratus and comparative evolution of woodpeckers.

De Novo Assembly of a Chromosome-Scale Reference Genome for the Northern Flicker Colaptes auratus

ABSTRACTThe northern flicker, Colaptes auratus, is a widely distributed North American woodpecker and a long-standing focal species for the study of ecology, behavior, phenotypic differentiation, and hybridization. We present here a highly contiguous de novo genome assembly of C. auratus, the first such assembly for the species and the first published chromosome-level assembly for woodpeckers (Picidae). The assembly was generated using a combination of short-read Chromium 10x and long-read PacBio sequencing, and further scaffolded with chromatin conformation capture (Hi-C) reads. The resulting genome assembly is 1.378 Gb in size, with a scaffold N50 of 43.948 Mb and a scaffold L50 of 11. This assembly contains 87.4 % - 91.7 % of genes present across four sets of universal single-copy orthologs found in tetrapods and birds. We annotated the assembly both for genes and repetitive content, identifying 18,745 genes and a prevalence of ~ 28.0 % repetitive elements. Lastly, we used four-fold degenerate sites from neutrally evolving genes to estimate a mutation rate for C. auratus, which we estimated to be 4.007 × 10−9 substitutions / site / year, about 1.5x times faster than an earlier mutation rate estimate of the family. The highly contiguous assembly and annotations we report will serve as a resource for future studies on the genomics of C. auratus and comparative evolution of woodpeckers.

Local recruitment in Northern Flickers is related to environmental factors at multiple scales and provides reproductive benefits to yearling breeders settling close to home

Natal dispersal and local recruitment are affected by factors both intrinsic and extrinsic to juveniles and may affect fitness. Understanding the relationship between dispersal and population density in birds has been hindered by a lack of long-term studies and a focus on resident species has neglected the role of weather operating at large spatial scales. I studied local recruitment and the reproductive consequences of natal dispersal distance within a population of Northern Flickers (Colaptes auratus), a migratory woodpecker. During a field study spanning 16 yr in British Columbia, 8,272 fledglings were banded and 138 males and 105 females recruited locally. The average annual local recruitment rate for males (3.36%) was greater than that for females (2.55%) and the propensity to recruit locally was positively correlated with an early hatch date and high body condition. Annual local recruitment was not associated with population density in the year of hatch but was positively correlated with population density in the year of settlement. Local recruitment was also positively correlated with warmer springs during migration, consistent with the phenology hypothesis that the location of settlement is affected by weather along the route. Among local recruits, natal dispersal distance was independent of the presence of parents and so dispersal was not a behavior to prevent inbreeding. However, settling closer to the natal site led to reproductive benefits in terms of earlier laying dates and better nest success. Therefore, juveniles may gain useful information about the location of nesting substrates, predation risk, and patchy food resources by exploring the landscape around their natal site during the post-fledging period and then settling in the familiar area after returning from migration.

Calling in the face of danger: Do nestling Red-winged Blackbirds (Agelaius phoeniceus) suppress begging in response to predator playbacks?

Nest predation is the most frequent cause of nest failure in birds such as the Red-winged Blackbird (Agelaius phoeniceus) that nest on or near the substrate. Nestlings should therefore exhibit adaptations to reduce the risk of nest predation. We tested the nestling antipredator hypothesis by examining the begging responses of Red-winged Blackbird nestlings to vocalizations of (1) an important nest predator (American Crow, Corvus brachyrhynchos), (2) a predator that rarely preys on nestlings (Cooper’s Hawk, Accipiter cooperii), and (3) a nonpredator (Northern Flicker, Colaptes auratus). We performed playbacks with (1) both parents present at the nest, (2) male at the nest, and (3) neither parent present. Following playback, we measured duration of nestling begging after the parent departed (begging persistence), bouts of otherwise normal begging when no parent was present (parent-absent begging), and calling without postural components of begging (nonpostural begging). When the male or both parents were present during playback, adults responded with alarm calls and nestlings significantly reduced parent-absent begging following American Crow and Cooper’s Hawk playbacks. Nonpostural begging was significantly reduced following Cooper’s Hawk playback, but there were no significant differences in the other begging variables. When neither parent was present, we found no significant differences in nonpostural begging in response to the 3 playback types, but parent-absent begging was significantly reduced following American Crow and Cooper’s Hawk playbacks when compared to Northern Flicker playbacks. These results show that nestlings suppress their vocal begging in response to calls of predators including Cooper’s Hawks even though they are not common nest predators.

Effects of biosolids amendments on American Kestrel (Falco sparverius) nest-site selection and diet

Fertilization is a common practice, as it improves plant yields. In many areas, biosolids (remains from treated wastewater) are used instead of chemical fertilizers owing to multi-year nutrient release and positive changes in soils and water retention. Little is known about whether biosolids affect animal consumers. Here, we examine diets and nesting sites of American Kestrels (Falco sparverius Linnaeus, 1758) in British Columbia, Canada. Our major study area was a large cattle ranch that has been grazed for over a century and where biosolids were applied in the previous 1–3 years. Kestrels selected nests in areas with higher Northern Flicker (Colaptes auratus (Linnaeus, 1758)) nest density and with a higher proportion of pastures with biosolids applications, but with less forest. Kestrels were observed more often on biosolids-amended pastures than in untreated areas. Kestrels primarily ate voles (genus Microtus Schrank, 1798), but also consumed grasshoppers (Orthoptera) late in the breeding season when grasshoppers were abundant. Kestrel diets were slightly more varied on a nearby control area than on the ranch. Our results suggest that biosolids applications improve prey availability for Kestrels, thus potentially acting as a restoration tool in areas with degraded habitats or where Kestrels have declined.