Observations on the use of dummy nests by fledgling Worthington's Marsh Wrens (Cistothorus palustris griseus)

Abstract Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) in Manitoba breed in dense colonies in cattail marshes. Their reproductive success is affected mainly by predation. The most important predator on blackbird nests is the Marsh Wren (Cistothorus palustris), which breaks blackbird eggs and kills small nestlings. We examined whether colonial nesting in Yellow-headed Blackbirds may represent an adaptation to reduce Marsh Wren predation. Marsh Wren predation may be reduced by (1) mutual nest defense by adult blackbirds, (2) predator satiation or dilution, or (3) selfish-herd effects. We tested these hypotheses using experimental nests and found that their safety increased with decreasing distance to the nearest blackbird nest and with increasing density of simultaneously active blackbird nests located nearby. Safety also was higher for nests placed inside a blackbird colony rather than outside. These findings support the nest-defense hypothesis. We also found that Marsh Wrens are capable of destroying a whole blackbird colony in a few days, and that colony size is not correlated with nest safety. These results suggest that the satiation or dilution benefits are negligible. Finally, we found that central nests are safer than peripheral nests in a blackbird colony, but not in an artificial colony, providing weak support for the selfish-herd hypothesis. We conclude that nest predation is reduced mainly by mutual nest defense of adult birds and may represent an important selective force favoring colonial nesting in this species.

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Marsh Wren (Cistothorus palustris)

10.2173/bna.308 ◽

2013 ◽

Cited By ~ 13

Author(s):

Donald E. Kroodsma ◽

Jared Verner

Keyword(s):

Cistothorus Palustris

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Geographic variation in call structure, likelihood, and call-song associations across subspecies boundaries, migratory patterns, and habitat types in the Marsh Wren (Cistothorus palustris)

The Auk ◽

10.1642/auk-17-110.1 ◽

2018 ◽

Vol 135 (1) ◽

pp. 127-151 ◽

Cited By ~ 2

Author(s):

Sarah A. M. Luttrell ◽

Bernard Lohr

Keyword(s):

Geographic Variation ◽

Habitat Types ◽

Call Structure ◽

Cistothorus Palustris ◽

Migratory Patterns

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Why Are Nesting Marsh Wrens and Yellow-Headed Blackbirds Spatially Segregated?

The Auk ◽

10.1093/auk/103.1.135 ◽

1986 ◽

Vol 103 (1) ◽

pp. 135-140 ◽

Cited By ~ 2

Author(s):

Marty L. Leonard ◽

Jaroslav Picman

Keyword(s):

Breeding Season ◽

The Other ◽

Cistothorus Palustris ◽

Xanthocephalus Xanthocephalus

Abstract The activity centers of Marsh Wrens (Cistothorus palustris) and Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) are spatially segregated. This segregation may occur because (1) one species excludes the other or (2) the two species prefer different habitats. These hypotheses were tested by documenting changes in the size and location of Marsh Wren territories throughout the breeding season, and by the removal of conesting Yellow-headed Blackbirds. The expansion of Marsh Wren territories into blackbird breeding areas after both the natural departure and the removal of blackbirds best supports the explanation based on the active exclusion of Marsh Wrens by Yellow-headed Blackbirds.

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Which characteristics might selection favour as cues of female choice of mate in Red-winged Blackbirds?

Canadian Journal of Zoology ◽

10.1139/z94-215 ◽

1994 ◽

Vol 72 (9) ◽

pp. 1616-1624 ◽

Cited By ~ 5

Author(s):

Maynard L. Milks ◽

Jaroslav Picman

Keyword(s):

Reproductive Success ◽

Nest Site ◽

Female Mate Choice ◽

Nest Defense ◽

Agelaius Phoeniceus ◽

Genetic Quality ◽

Cistothorus Palustris ◽

Site Characteristics ◽

Mammalian Predators ◽

Nest Height

In this study, we investigated potential cues determining choice of mate by female Red-winged Blackbirds (Agelaius phoeniceus) by examining male and nest-site characteristics that (i) affect the reproductive success of females, (ii) can be assessed by females prior to mating, and (iii) vary among potential mates, in 1983–1985. The 17 characteristics considered reflected the accessibility of redwing nests to mammalian predators and to Marsh Wrens (Cistothorus palustris), the importance of cooperation between female redwings in nest defense, and the paternal quality (feeding and defense of nestlings), genetic quality, physical condition, and size of redwing males. Only 4 characteristics, distance to nearest wren nest, distance to nearest simultaneously active conspecific nest, height of vegetation supporting the nest, and nest defense effort of males, met all of the above criteria in at least 1 year. Of these, proximity to wren nests appeared to satisfy the requirements most consistently in time and space, and thus might be the most likely to affect female redwing choice of mate. However, experimental manipulations are needed to ascertain whether any of these characteristics are cues of female mate choice in Red-winged Blackbirds.

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