Indirect estimates of breeding and natal philopatry in an obligate avian brood parasite

Abstract

In theory, obligate brood parasitic birds are freed from several of the temporal and spatial constraints of parental care for dependent young. Yet, similar to parental bird species, adults in several avian brood parasites show a territorial spacing system while breeding, including site fidelity within and across years. Banding-based capture and sighting studies are also suggestive of non-parasite-like lower levels of natal philopatry in avian brood parasites. We analyzed the potential correlation of physical distance with genetic structure of a Brown-headed Cowbird Molothrus ater population, sampling parasitic chicks from nests across different temporal and spatial scales of its common host, the Eastern Phoebe Sayornis phoebe, near Ithaca, New York, USA. In support of extensive breeding but not historical patterns of natal philopatry, we detected no significant covariation of genetic similarity by distance of nestling parasites at the scale beyond that of individual host nest sites. These results contribute towards a baseline for future behavioral and genetic comparisons of whether and how parasitic versus parental reproductive strategies impact patterns of avian population genetic structure across space and time.

How to Spot a Stranger's Egg? A Mimicry‐Specific Discordancy Effect in the Recognition of Parasitic Eggs

“…This finding probably has more relevance for systems where parasites repeatedly target or multiple parasites lay in hosts nests (Hauber et al. ), for example, with multiple cuckoo eggs laid by the same or different female cuckoos (Wyllie ), which is common in our great reed warbler population (Moskát et al. ).…”

Social Interactions between Adult and Juvenile Striped Cuckoos (Tapera naevia)

“…While we cannot know if the adults in this study were related to the juveniles with whom they associated, the juveniles fledged from nests of Rufousand-white Wrens located within their exclusive home ranges. If a Striped Cuckoo female is able to prevent competition from neighboring females for host nests through territory defense, she could be relatively certain that fledgling cuckoos she encountered were her offspring (Hoover et al 2006, Langmore et al 2007, Hauber et al 2012). Although we have limited data, it was often the adult who initiated social interactions.…”

A generalist brood parasite modifies use of a host in response to reproductive success

“…As a cavity nesting passerine, the prothonotary warbler could offer cowbirds a unique nestling experience and search image compared with other available species within the host community. While many adult brood parasitic species exhibit breeding site fidelity [30,[54][55][56], natal philopatry for cowbirds is considered uncommon [57]. Because cowbirds do not breed until 1 year old [11], the effects of egg removal on parasitism rates between consecutive breeding attempts within a given year (i.e.…”