A Documented History of Ring-Billed Gull and California Gull Colonies in the Western United States

Conover, Michael R.; Conover, Denise O.

doi:10.2307/1521109

Cited by 22 publications

(55 citation statements)

References 16 publications

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“…The ring-billed gull in the western U.S. feeds more in upland habitats, consuming insects and grain, while the California gull eats more carrion'and garbage (Rothweiler 1960, Anderson 1965, Vermeer 1970). These differences in food habits may explain the large increases in the ring-billed populations compared to the California gull in the western United States, paralleling corresponding increases in farming activities (Conover 1983). Decreased predation by man (mainly for eggs and plumage) and other predators may also play a role in the increasing gull populations.…”

Section: Gullsmentioning

confidence: 98%

“…Decreased predation by man (mainly for eggs and plumage) and other predators may also play a role in the increasing gull populations. Worlcwide increases in other gull species have also been documented (reviewed in Conover 1983). …”

Section: Gullsmentioning

confidence: 98%

“…Similar increases have taken place in ring-billed gull populations around the Great Lakes region (Ludwig 1974, Blokpoel 1977, Blokpoel and McKeating 1978, Scharf et al 1978, Blokpoel and Tessier 1984, Forbes 1988). Both of these species breed inland and apparently have prospered from the increased food supply provided by garbage dumps (including their rodent and insect populations) and agricultural crop land (especially grain fields and the associated insect and rodent fauna), as well as an increase in breeding habitat on islands formed by manmade reservoirs (Conover 1983). Colonies of these species, especially the ring-billed, appear to be thriving in the proximity of irrigated agricultural land (Baird 1977, Conover 1983.…”

Section: Gullsmentioning

confidence: 99%

“…Both of these species breed inland and apparently have prospered from the increased food supply provided by garbage dumps (including their rodent and insect populations) and agricultural crop land (especially grain fields and the associated insect and rodent fauna), as well as an increase in breeding habitat on islands formed by manmade reservoirs (Conover 1983). Colonies of these species, especially the ring-billed, appear to be thriving in the proximity of irrigated agricultural land (Baird 1977, Conover 1983. The ring-billed gull in the western U.S. feeds more in upland habitats, consuming insects and grain, while the California gull eats more carrion'and garbage (Rothweiler 1960, Anderson 1965, Vermeer 1970).…”

Section: Gullsmentioning

confidence: 99%

“…Percent increase in total population size 2100% 173% *Data calculated from Conover 1983. in their diet*, even in the two urban studies (Greenhalgh 1952, Haymes and. In Conover's (1983) extensive review of the increasing populations of ring-billed and California gulls he concluded that further increases in their populations should be encouraged, whenever local conditions permit, because they feed on agricultural pests and for their beauty and aesthetic value.…”

Section: Gullsmentioning

confidence: 99%

See 4 more Smart Citations

Birds in Human Modified Environments and Bird Damage Control: Social, Economic, and Health Implications

Krzysik¹

1989

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Section: Gullsmentioning

confidence: 98%

Section: Gullsmentioning

confidence: 98%

Section: Gullsmentioning

confidence: 99%

Section: Gullsmentioning

confidence: 99%

Section: Gullsmentioning

confidence: 99%

See 3 more Smart Citations

Birds in Human Modified Environments and Bird Damage Control: Social, Economic, and Health Implications

Krzysik¹

1989

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Dependence of spatial scale in landscape associations with cause‐specific predation of snowy plover nests

2020

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Understanding relationships between habitat and ecological processes often depends on the spatial scale at which the landscape is measured. A common objective in studies of avian nesting ecology is to link habitat characteristics with nest predation for generating potential conservation and management strategies aimed at increasing avian reproductive success. Yet scale dependence likely plays a considerable role in these assessments, particularly when multiple species of nest predators are present. We identified nest predators of snowy plovers, a ground-nesting shorebird, and modeled predator-specific hazard rates of nest mortality in relation to the landscape at multiple spatial scales (200 m, 500 m, 1 km, 2.5 km, and 5 km) and at the nest site. We used a Bayesian latent indicator approach for weighting the influence of habitat across spatial scales and to gain insight into the hierarchical nature of how specific predators responded to the landscape when preying upon plover nests. We did not identify a common spatial scale that best predicted nest predation by all predators, though our results indicated that unfragmented playa and marsh habitats at large spatial scales reduced nest predation by all nest predators. Land cover features including grass, shrubs, human development, and open water elicited variable responses depending on the predator group, and predator groups responded at different spatial scales. Further, the spatial configuration of nests (nest dispersion) influenced nest predation by common ravens Corvus corax and foxes (kit fox Vulpes macrotis and red fox Vulpes vulpes), suggesting that certain predators develop a search image for nests. Our results illustrate that clarifying complex relationships between nest predation and habitat characteristics requires the incorporation of predator identity and scale dependence. Thus, management and conservation plans aiming to increase avian productivity by altering or restoring habitats will likely benefit from consideration of predator-specific patterns at multiple spatial scales.

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Forster's tern chick survival in response to a managed relocation of predatory California gulls

et al. 2014

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Gull populations can severely limit the productivity of waterbirds. Relocating gull colonies may reduce their effects on nearby breeding waterbirds, but there are few examples of this management strategy. We examined gull predation and survival of Forster's tern (Sterna forsteri) chicks before (2010) and after (2011) the managed relocation of the largest California gull (Larus californicus) colony (24,000 adults) in San Francisco Bay, California. Overall, survival of radio‐marked Forster's tern chicks from hatching to fledging was 0.22 ± 0.03 (mean ± SE), and daily survival rates increased with age. Gulls were the predominant predator of tern chicks, potentially causing 54% of chick deaths. Prior to the gull colony relocation, 56% of radio‐marked and 20% of banded tern chicks from the nearest tern colony were recovered dead in the gull colony, compared to only 15% of radio‐marked and 4% of banded chicks recovered dead from all other tern colonies. The managed relocation of the gull colony substantially increased tern chick survival (by 900%) in the nearby (<1 km) colony from 0.04 ± 0.02 in 2010 to 0.40 ± 0.12 in 2011 but not at the more distant (>3.8 km) reference tern colony (0.29 ± 0.10 in 2010 and 0.25 ± 0.09 in 2011). Among 19 tern nesting islands, fledging success was higher when gull abundance was lower at nearby colonies and when gull colonies were farther from the tern colony. Our results indicate that the managed relocation of gull colonies away from preferred nesting areas of sensitive waterbirds can improve local reproductive success, but this conservation strategy may shift gull predation pressure to other areas or species. © 2014. This article is a U.S. Government work and is in the public domain in the USA.

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A Documented History of Ring-Billed Gull and California Gull Colonies in the Western United States

Cited by 22 publications

References 16 publications

Birds in Human Modified Environments and Bird Damage Control: Social, Economic, and Health Implications

Birds in Human Modified Environments and Bird Damage Control: Social, Economic, and Health Implications

Dependence of spatial scale in landscape associations with cause‐specific predation of snowy plover nests

Forster's tern chick survival in response to a managed relocation of predatory California gulls

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