Extra-pair paternity in a species with frequent extra-pair courtship feedings, few extra-pair copulations, and male-biased parental care

Patterns of extra pair paternity (EPP) and intraspecific brood parasitism (IBP) were studied in a Whiskered Tern Chlidonias hybrida population characterized by female brood desertion, a high level of extra pair courtship feedings (10%) and a low level of extra pair copulation (EPC; 0.6%). In this study, we used a set of microsatellite loci to analyse parentage in 56 Whiskered Tern families from southern Poland. Depending on the method, we detected that 1.4%–3.6% of chicks were sired by an extra-pair male, and extra-pair chicks were present in 3.6%–8.9% of broods. IBP was observed in 8.9%–14.3% of broods, corresponding to 3.6%–6.4% of the chicks. The low rate of EPP is in agreement with the hypothesis that in species with high male parental investment, females should avoid EPC. The low level of IBP indicates that intraspecific egg dumping is not a common female strategy in Whiskered Tern, similar to many other colonial waterbird species.

High level of extra-pair paternity in the socially monogamous Marsh Tits (Poecile palustris)

Background Extra-pair copulation behavior has been widely studied among socially monogamous birds. Many species revealed high rates of extra-pair paternity. But few of the studies have been carried out in the Asian population. Methods From 2012 to 2019, we explored the extra-pair paternity of Marsh Tits (Poecile palustris) in Xianrendong National Nature Reserve, Liaoning Province, China. During the study, adult Marsh Tits were captured with mist nets and parental birds, with nest-box traps. Blood samples were taken from the brachial vein. Parentage analyses were carried out using nine highly variable microsatellite loci through Cervus 3.0 software and maximum likelihood approach. Results Forty-nine offspring (15.08%) from 20 nests (45.45%) were the results of extra-pair fertilization out of a total of 325 offspring in 44 nests. The average extra-pair offspring ratio was 33.54%, with a set varying from 11.11 to 71.43%. Nine extra-pair fathers had been successfully identified, four of whom were the close neighbors of the focus nest while the nests of the remaining five were relatively far. No significant difference was found in the genetic similarity between the social and extra-pair mates of the female, nor in the heterozygosis among the maternal half-siblings. Conclusions In general, our study proved that the extra-pair paternity in Marsh Tits and its extra-pair mating is independent of the genetic compatibility hypothesis. This complements the understudied bird’s extra-pair paternity in Asian area and contributes to the comprehensive insight of birds’ extra-pair paternity behaviors.

First microsatellite markers for the European Robin (Erithacus rubecula) and their application in analysis of parentage and genetic diversity

The European Robin is a small passerine bird associated with woodlands of Eurasia and North Africa. Despite being relatively widespread and common, little is known of the species’ breeding biology and genetic diversity. We used Next Generation Sequencing (NGS) to develop and characterize microsatellite markers for the European Robin, designing three multiplex panels to amplify 14 microsatellite loci. The level of polymorphism and its value for assessing parentage and genetic structure was estimated based on 119 individuals, including seven full families and 69 unrelated individuals form Poland’s Białowieża Primaeval Forest and an additional location in Portugal. All markers appeared to be highly variable. Analysis at the family level confirmed a Mendelian manner of inheritance in the investigated loci. Genetic data also revealed evidence for extra-pair paternity in one family. The set of markers that we developed are proven to be valuable for analysis of the breeding biology and population genetics of the European Robin.

Report of an extra-pair copulation in the Rufous Hornero, Furnarius rufus (Aves: Furnariidae)

In the last decade, studies in bird breeding biology have shown that infidelity is prevalent in socially monogamous species. Here, we describe an extra-pair copulation (EPC) event in the Rufous Hornero (Furnarius rufus), a socially monogamous bird with year-round territoriality and low levels of extra-pair paternity. Before the EPC, a within-pair copulation (WPC) occurred inside the pair’s territory. The WPC occurred on the ground and between a banded male (ca. 6 years-old) and an unbanded female. Ten minutes later this breeding pair invaded a neighboring territory, presumably to forage. The territorial male was chased back to its territory by an unbanded male neighbor after being detected. The male neighbor was paired with an unbanded female that did not participate in the aggressive interaction. When flying back to its territory the male neighbor copulated with the territorial female on the ground (ie. EPC). The territorial male flew, vocalized, and perched above the male neighbor, interrupting the EPC. The aggressive interaction then ceased as each pair resumed foraging in their respective territories. These observations suggest that Rufous Horneros can use EPC to obtain immediate benefits (food access in a neighbor’s territory). Moreover, WPC may be detected by neighbors and physical mate guarding and/or frequent WPC may be necessary to prevent EPC in the Rufous Hornero.