High Frequency of Extra-Pair Paternity in Eastern Kingbirds

Abstract Genetic parentage in the socially monogamous and territorial Eastern Kingbird (Tyrannus tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitism) or both (conspecific brood parasitism) of the putative parents. In the New York population, extra-pair paternity was most common among females that returned to breed on a former territory. Among females that were new to a breeding territory, extra-pair paternity increased directly with breeding density. Although the power of the tests was low, neither breeding synchrony nor male experience with a breeding territory appeared to be associated with the occurrence of extra-pair young. Alta Frecuencia de Paternidad Extra-Pareja en Tyrannus tyrannus Resumen. Se examinó la paternidad genética de Tyrannus tyrannus, especie socialmente monógama y territorial, mediante la técnica de huellas dactilares genéticas de múltiples loci en una población de Nueva York central. En el 60% (12 de 20) de los nidos se identificaron juveniles con origen extra-pareja. De los 64 pichones investigados, el 42% fue engendrado por machos fuera de la pareja, aunque no se detectaron nidadas con parasitismo conespecífico. Estos resultados son considerablemente diferentes a los obtenidos en un estudio previo para la misma especie en una población de Michigan, el cual reportó que el 39% de los pichones no estaban relacionados con uno (tipicamente a la madre, cuasiparasitismo) o ambos (parasitismo de nido conespecífico) padres putativos. En la población de Nueva York, la paternidad extra-pareja fue más común entre hembras que retornaron a criar a territorios que habían ocupado previamente. Entre las hembras que ocuparon por primera vez un territorio de cría, la paternidad extra-pareja aumentó directamente con la densidad de individuos reproductivos. A pesar que el poder del análisis fue bajo, ni la sincronía reproductiva, ni la experiencia de los machos en sus territorios de cria, parecen estar asociados a la ocurrencia de juveniles extra-pareja.

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Extra-pair paternity and mate-guarding behaviour in the brown thornbill

Australian Journal of Zoology ◽

10.1071/zo02037 ◽

2002 ◽

Vol 50 (6) ◽

pp. 565 ◽

Cited By ~ 5

Author(s):

David J. Green ◽

Anne Peters ◽

Andrew Cockburn

Keyword(s):

Mate Guarding ◽

Male Size ◽

Fertile Period ◽

Young Males ◽

Extra Pair Paternity ◽

Close Proximity ◽

Multilocus Dna Fingerprinting ◽

Socially Monogamous ◽

The Relationship ◽

Older Males

We used multilocus DNA fingerprinting to assess parentage in the brown thornbill, Acanthiza pusilla, a socially monogamous Australian passerine. Extra-pair paternity was uncommon (6.2% of 178 offspring; 11.9% of 67 broods) and there was no evidence of intra-specific brood parasitism. Extra-pair paternity was limited because pairs spent more time together when females were fertile and males were able to evict intruding males before they could approach the female. Males were responsible for the close proximity of partners during the fertile period. Mate guarding therefore appears to be a male tactic aimed at preventing female infidelity rather than a cooperative behaviour of the pair aimed at preventing extra-pair copulations and/or female harassment. Females did not attempt to escape male guarding and were rarely observed to solicit copulations from intruding males. Nevertheless, females paired to smaller and younger males were more likely to cuckold their mates than females paired to larger and older males. This suggests that females may be more likely to seek or accept extra-pair matings when paired to small, young males or that old, large males are better at preventing their mates from engaging in extra-pair copulations. We found that male age but not male size influences mate-guarding behaviour. Older males tended to respond more aggressively to intruders. We therefore speculate that the relationship between male size/age and extra-pair paternity in brown thornbills may arise because female thornbills prefer large males as mates but are unable to express this preference as easily when paired to older males.

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Variation in incubation length and hatching asynchrony in Eastern Kingbirds: Weather eclipses female effects

The Auk ◽

10.1093/ornithology/ukab031 ◽

2021 ◽

Author(s):

Samantha M Gillette ◽

Amanda L Klehr ◽

Michael T Murphy

Keyword(s):

New York ◽

Clutch Size ◽

Egg Laying ◽

Hatching Asynchrony ◽

Ambient Temperatures ◽

Temperature And Precipitation ◽

Incubation Periods ◽

Tyrannus Tyrannus ◽

Eastern Kingbird ◽

Small Clutch

Abstract Incubation length and hatching asynchrony are integral elements of the evolved reproductive strategies of birds. We examined intra- and interpopulation variation in both traits for Eastern Kingbird (Tyrannus tyrannus) populations from New York (NY), Kansas (KS), and Oregon (OR) and found that both incubation length and hatching asynchrony were not repeatable among females, after controlling for a repeatable trait, clutch size. Instead, incubation length and clutch size were influenced by ambient temperature and precipitation. Incubation length exhibited the same median (15 days) and range (13–17 days) at all sites. Model selection results indicated that incubation periods for the smallest and largest clutches were longer in NY than KS when rain was frequent throughout incubation, in replacement nests, and likely when ambient temperatures were low during egg-laying. Full hatching usually required 2 days (but up to 3), with synchronous hatching associated with small clutch sizes, short incubation periods, frequent rain during the egg-laying period, and low ambient temperatures during the first half of incubation. Nestling starvation was uncommon (5–9% of nestlings monitored) and not associated with greater hatching asynchrony. These results indicate that while clutch size, a repeatable female trait, contributed to variation in incubation length and hatching asynchrony in Eastern Kingbirds, weather was a greater source of variation, especially for incubation length.

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