Forster's Tern (Sterna forsteri)

McNicholl, Martin K.; Lowther, Peter E.; Hall, John A.

doi:10.2173/bna.595

Cited by 25 publications

(46 citation statements)

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“…Island areas were obtained from recent publications Leatherman et al 1995;Wray 1992) for the some of the larger islands (>75 ha) in the Bay. Areal estimates of selected islands from the Leatherman et al (1995) report were recently updated with 2007 imagery for some Maryland islands (DFB).…”

Section: Island Characteristicsmentioning

confidence: 99%

“…Areal estimates of selected islands from the Leatherman et al (1995) report were recently updated with 2007 imagery for some Maryland islands (DFB). Maryland aerial images (digital ortho-corrected) were acquired from the Maryland Department of Natural Resources during 2007 for estimating the area of smaller islands.…”

Section: Island Characteristicsmentioning

confidence: 99%

“…The criteria included: (1) a true island at least 0.1 ha in area that is not inundated on daily high tides; (2) island has no permanent human habitation; and (3) is not connected or within close proximity (<2 km) to a mainland marsh that may support mammalian predators. The DOQQ images for Virginia used to estimate the number of islands in the Virginia portion of the Bay were from the early 1990s imagery (C. Gist, University of Virginia GeoSpatial Center) Table 1 Historic losses of large island in Chesapeake Bay (modified from Leatherman et al 1995 ); the figure (1,400 acres) from Leatherman et al (1995) included the entire complex, including Jefferson and Coaches Islands c D. Brinker, unpubl., digital orthoimage measurements; at St. Clements Island, erosion control using riprap began in the early 1980s, so there has been no change in area in the past two decades, comparing figures of Leatherman et al (1995 and from 1988 to 1995 for Maryland (DFB, Maryland Department of Natural Resources data files). For the Tangier Sound study area in Virginia, 1994 aerial photography was compared with 2007 photography.…”

Section: Island Characteristicsmentioning

confidence: 99%

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Islands at bay: rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

et al. 2010

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Like many resources in the Chesapeake Bay region of the U.S., many waterbird nesting populations have suffered over the past three to four decades. In this study, historic information for the entire Bay and recent results from the Tangier Sound region were evaluated to illustrate patterns of island erosion and habitat loss for 19 breeding species of waterbirds. Aerial imagery and field data collected in the nesting season were the primary sources of data. From a group of 15 islands in Tangier Sound, Virginia were reduced by 21% in area, as most of their small dunes and associated vegetation and forest cover were lost to increased washovers. Concurrently, nesting American black ducks (Anas rubripes) declined by 66% , wading birds (herons-egrets) by 51%, gulls by 72%, common terns (Sterna hirundo) by 96% and black skimmers (Rynchops niger) by about 70% in this complex. The declines noted at the larger Bay-wide scale suggest that this study area maybe symptomatic of a systemic limitation of nesting habitat for these species. The island losses noted in the Chesapeake have also been noted in other Atlantic U. S. coastal states. Stabilization and/or restoration of at least some of the rapidly eroding islands at key coastal areas are critical to help sustain waterbird communities.

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Section: Island Characteristicsmentioning

confidence: 99%

Section: Island Characteristicsmentioning

confidence: 99%

Section: Island Characteristicsmentioning

confidence: 99%

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Islands at bay: rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

et al. 2010

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“…Forster's terns have semi-precocial young that are fed by their parents on nesting colonies until they fledge at about 28 days of age (McNicholl et al 2001). Thereafter, postfledging terns are capable of flight and autonomous foraging.…”

Section: Introductionmentioning

confidence: 99%

“…Forster's tern chicks exhibit elevated blood mercury concentrations just before and during fledging (Ackerman et al 2007a) and may therefore experience increased risk of mortality due to mercury exposure. Forster's terns are an ideal species to examine the influence of mercury on postfledging survival because they forage at a high trophic level (McNicholl et al 2001) in shallow-water wetlands along San Francisco Bay's margins (Ackerman et al 2008b) where methyl mercury production is high (MarvinDiPasquale et al 2003). Moreover, Forster's terns are one of the most common piscivorous waterbirds breeding in San Francisco Bay, making them a good indicator of mercury exposure and effects to fledgling waterbirds.…”

Section: Introductionmentioning

confidence: 99%

Survival of postfledging Forster’s terns in relation to mercury exposure in San Francisco Bay

et al. 2008

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We examined factors influencing mercury concentrations in 90 fledgling Forster's terns (Sterna forsteri) and evaluated whether mercury influenced postfledging survival in San Francisco Bay, California. Mercury concentrations (+/- SE) in chicks 21-29 days old (just before fledging) were 0.33 +/- 0.01 microg g(-1) ww for blood and 6.44 +/- 0.28 microg g(-1) fw for breast feathers. Colony site had an overriding influence on fledgling contamination, however hatching date and age also affected blood, but not feather, mercury concentrations. Blood mercury concentrations decreased by 28% during the 50-day hatching period and increased with chick age by 30% during the last week prior to fledging. Using radio-telemetry, we calculated that cumulative survival during the 35-day postfledging time period was 0.81 +/- 0.09 (SE). Postfledging survival rates increased with size-adjusted mass, and cumulative survival probability was 61% lower for terns with the lowest, compared to the highest, observed masses. Conversely, survival was not influenced by blood mercury concentration, time since fledging, sex, or hatch date. Mercury concentrations in breast feathers of fledglings found dead at nesting colonies also were no different than those in live chicks. Our results indicate that colony site, hatching date, and age influenced mercury concentrations in fledgling Forster's terns, but that mercury did not influence postfledging survival.

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Embryo malposition as a potential mechanism for mercury‐induced hatching failure in bird eggs

Herring

Ackerman

Eagles‐Smith

2010

Enviro Toxic and Chemistry

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We examined the prevalence of embryo malpositions and deformities in relation to total mercury (THg) and selenium (Se) concentrations in American avocet (Recurvirostra americana), black-necked stilt (Himantopus mexicanus), and Forster's tern (Sterna forsteri) eggs in San Francisco Bay (CA, USA) during 2005 to 2007. Overall, 11% of embryos were malpositioned in eggs > or =18 d of age (n = 282) and 2% of embryos were deformed in eggs > or =13 d of age (n = 470). Considering only those eggs that failed to hatch (n = 62), malpositions occurred in 24% of eggs > or =18 d of age and deformities occurred in 7% of eggs > or =13 d of age. The probability of an embryo being malpositioned increased with egg THg concentrations in Forster's terns, but not in avocets or stilts. The probability of embryo deformity was not related to egg THg concentrations in any species. Using a reduced dataset with both Se and THg concentrations measured in eggs (n = 87), we found no interaction between Se and THg on the probability of an embryo being malpositioned or deformed. Results of the present study indicate that embryo malpositions were prevalent in waterbird eggs that failed to hatch and the likelihood of an embryo being malpositioned increased with egg THg concentrations in Forster's terns. We hypothesize that malpositioning of avian embryos may be one reason for mercury-related hatching failure that occurs late in incubation, but further research is needed to elucidate this potential mechanism.

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Forster's Tern (Sterna forsteri)

Cited by 25 publications

References 0 publications

Islands at bay: rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

Islands at bay: rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

Survival of postfledging Forster’s terns in relation to mercury exposure in San Francisco Bay

Embryo malposition as a potential mechanism for mercury‐induced hatching failure in bird eggs

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