Cognition and the brain of brood parasitic cowbirds

Abstract

Cowbirds are brood parasites. Females lay their eggs in the nests of other species which then incubate the cowbird eggs and raise the young cowbirds. Finding and returning to heterospecific nests presents cowbirds with a number of cognitive challenges. In some species, such as brown-headed cowbirds (Molothrus ater), females but not males, search for and remember the locations of potential host nests. We describe recent research on sex differences in cognition and the hippocampus associated with this sex difference in search for host nests. Female brown-headed cowbirds perform better than males on some, but not all, tests of spatial memory and females show a pattern of adult hippocampal neurogenesis not found in males or in closely related non-parasitic birds. Because of the apparent specialization of the hippocampus, brown-headed cowbirds may be a good model in which to examine spatial information processing in the avian hippocampus and we also describe recent research on the spatial response properties of brown-headed cowbird hippocampal neurons. This article is protected by copyright. All rights reserved.

No evidence for cross-contextual consistency in spatial learning and behavioural flexibility in a passerine

“…For example, a current focus of research in food caching species is to measure spatial learning under standardised conditions, usually on a small scale, to infer performance in cache retrieval at a larger spatial scale, or to predict fitness, but it remains unclear whether observed associations relate to navigation through the environment or cache retrieval at a fine spatial scale (Healy, 2019;Healy et al, 2005Healy et al, , 2009Krebs et al, 1990;McGregor & Healy, 1999). Similarly, work on parasitic cowbirds in which the females, but not males, need to locate and remember potential host nests, have found that females out-perform males in some spatial learning tasks, but not others, further suggesting that individual differences in spatial ability may depend on task design and scale of spatial location (Sherry & Guigueno, 2019). This limitation mirrors the more general problem in evolutionary ecological studies of cognition where there is often a lack of a clear link between standardised cognitive tests (e.g.…”

Animal cognition

“…Her mate very much leaves her to it. Sherry and Guigeno (2019) found that female brown-headed cowbirds outperformed conspecific males in 1 spatial task but not another and that females had greater hippocampal neurogenesis than did males, a sex difference not seen in red-winged blackbirds, Agelaius phoeniceus, a closely related species that is not a brood parasite. An association between neural data and performance on one apparently spatial task but on not another causes us to examine more closely what ability the animal might actually use to perform well in tests we assume assess a particular cognitive ability (for Sherry & Guigeno, spatial memory).…”

No Evidence for Cross-Contextual Consistency in Spatial Cognition or Behavioral Flexibility in a Passerine

“…For example, a current focus of research in food caching species is to measure spatial cognition under standardized conditions, usually on a small scale, to infer performance in cache retrieval at a larger spatial scale, but it remains unclear whether observed associations relate to navigation through the environment, or cache retrieval at a fine spatial scale (Healy, 2019;Healy et al, 2005Healy et al, , 2009Krebs et al, 1990;McGregor & Healy, 1999). Similarly, work on parasitic cowbirds in which the females, but not males, need to locate and remember potential host nests, have found that females outperform males in some spatial cognition tasks, but not others, further suggesting that individual differences in spatial ability may depend on task design and scale of spatial location (Sherry & Guigueno, 2019). This limitation mirrors the more general problem in evolutionary ecological studies of cognition, where there is often a lack of a clear link between standardized cognitive tests (e.g., problem solving) and functional behavior (innovative foraging) under natural conditions (Morand-Ferron et al, 2016;Rowe & Healy, 2014a, b;Thornton et al, 2014).…”