Site fidelity and territorial movements of males in a rapidly declining population of yellow-headed blackbirds

Beletsky, Les D.; Orians, Gordon H.

doi:10.1007/bf00183476

Cited by 23 publications

(16 citation statements)

References 18 publications

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“…Once located, nests were monitored once a week until they either failed or fledged young. I compared the number of young fledged per nest attempt and per successful nest (nests that fledged at least one nestling) with data from other Yellow-headed Blackbird populations in Washington ( Willson 1966;Patterson et al 1980;Beletsky & Orians 1994), Manitoba (Lightbody 1986;Forbes et al 2002), Iowa (Ammann 1938;Richter 1984), and Wisconsin (Minock 1985).…”

Section: Reproductive Success and Adult Survivalmentioning

confidence: 99%

The Role of Immigration in the Decline of an Isolated Migratory Bird Population

Ward

2005

Conservation Biology

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Low immigration is rarely considered a potential causal factor in the population decline of migratory birds. Because migratory songbirds exhibit low natal philopatry, however, recruitment is from outside the population. Therefore, if isolation affects immigration the geographic fragmentation of a species' range may result in population declines. I tested four hypotheses on the possible causes of population decline of an isolated population of Yellow‐headed Blackbirds (Xanthocephalus xanthocephalus) in Illinois (U.S.A.): (1) local habitat loss, (2) poor reproductive success, (3) low adult survival, and (4) low immigration. Historical accounts indicate this population has declined and become more isolated over the last century. From 1998 to 2003, I determined the population size, the annual return rate, and mean reproductive success of Yellow‐headed Blackbirds in Illinois. I also determined the amount of suitable habitat for the species in the area. Over the course of the study the population declined by 25%. Although habitat loss was likely to be responsible for the population's historical decline, currently the habitat is not saturated and many seemingly appropriate sites remain unoccupied. The reproductive success of the Illinois population is one of the highest recorded for this species. Adult survival was within the range of survival values found in other stable populations. Yellow‐headed Blackbirds, like most migratory passerines, exhibit low natal philopatry; therefore, recruitment is primarily from outside the population. Recruitment was unusually low in this population, suggesting the population's isolation on the periphery of the species' range has reduced the number of immigrants. Although individuals in the population had high survival and reproduction, the population continued to decline because of low immigration. Conventional management (i.e., restoring habitat) may not mitigate a population's decline if low immigration is responsible for the decline. Greater connectivity at a large scale may be necessary to conserve isolated populations of migratory birds.

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Section: Reproductive Success and Adult Survivalmentioning

confidence: 99%

The Role of Immigration in the Decline of an Isolated Migratory Bird Population

Ward

2005

Conservation Biology

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“…However, many wildlife populations are not at equilibrium. Habitats may not be saturated when populations are declining (Beletsky and Orians 1994)o r expanding their geographic range (Williams et al 1994). The case of invasive species is a typical example of increasing populations whose geographic range is expanding (Sakai et al 2001;Smith et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Evidence for density‐dependent habitat occupancy at varying scales in an expanding bird population

Gadenne¹,

Cornulier²,

Éraud³

et al. 2014

Population Ecology

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Understanding factors shaping the spatial distribution of animals is crucial for the conservation and management of wildlife species. However, few studies have investigated density-dependent habitat selection in wild populations in non-equilibrium conditions and at varying spatial scales. Here, we investigated densitydependent habitat selection at varying spatial scales in an increasing white stork Ciconia ciconia population using a long term data set in western France. During a 16-year study period, the breeding population density increased from 0.66 nests per 100 km 2 to 6.6 nests per 100 km 2 .A t the beginning of the colonisation of the area settlement probability of storks was mainly positively affected by grasslands located near wetlands. Areas with intensive or moderately intensive agriculture were extremely unlikely to be occupied by breeding birds. However, selection for the initially preferred habitats faded as stork density increased although the proportions of habitat types remained unchanged. At the same time selection for initially less favoured habitats had increased. Moreover, we found that the spatial scale of selection for each foraging habitat variable was consistent over time. Our results suggest that snapshot analyses of resource selection in populations at high density may be misleading for population conservation or management. In contrast, a longitudinal approach to resource selection can be a valuable tool for understanding resource limitation.

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“…Gaston, 1994;Simberloff, 1994;Thomas, 1994); (iii) low vagility or high site fidelity, so that the taxon is unlikely to colonize available habitat patches unless they are easily accessible to existing populations (e.g. Wiens, Rotenberry & Van Horne, 1986;Warren, 1987;Bierregaard et al, 1992;Belettsky & Orians, 1994;Wiens, 1994); and (iv) low recruitment rates, so that the population is unable to maintain its numbers in the face of additional sources of mortality (e.g. Glazier, 1980;Pimm et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Ecological characteristics of a threatened snake species, Hoplocephalus bungaroides (Serpentes, Elapidae)

Webb

Shine

1998

Animal Conservation

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Species with ecological (habitat, dietary) specialization and low reproductive output may be at particular risk from anthropogenic habitat disturbance. We studied growth, reproduction and diet of the threatened broad-headed snake (Hoplocephalus bungaroides), a small nocturnal elapid from sandstone habitats in south-eastern Australia. Our data suggest that the life-history traits and diets of broadheaded snakes contribute to their vulnerability. Rather than searching actively for prey (like most sympatric elapids), broad-headed snakes wait under rocks to ambush prey. In consequence, these snakes feed infrequently, grow slowly, mature late and reproduce infrequently (compared with other sympatric snake species). Because of an ontogenetic shift in food habits, populations of broad-headed snakes require access to high densities of velvet geckos (in rock outcrops) as well as small mammals (in adjacent woodland). The specialized diet, reliance upon two distinctive habitats, low rate of growth, delayed maturation and low reproductive output may have exacerbated the vulnerability of broadheaded snakes to habitat destruction. All of these traits may be due to the species' reliance upon ambush predation rather than active foraging. A broader analysis supports the hypothesis that foraging mode may contribute to endangerment: a disproportionate number of 'threatened' species of Australian elapid snakes rely on ambush predation.

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Site fidelity and territorial movements of males in a rapidly declining population of yellow-headed blackbirds

Cited by 23 publications

References 18 publications

The Role of Immigration in the Decline of an Isolated Migratory Bird Population

The Role of Immigration in the Decline of an Isolated Migratory Bird Population

Evidence for density‐dependent habitat occupancy at varying scales in an expanding bird population

Ecological characteristics of a threatened snake species, Hoplocephalus bungaroides (Serpentes, Elapidae)

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