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Geology topics

I.C.T. Nisbet

Publications and source records attributed to I.C.T. Nisbet.

15 recordsLinked to original sources
USGS2008

Temporal variation in adult survival rates of Roseate Terns during periods of increasing and declining populations

We used 19 years of mark-recapture/resighting data collected on 11, 020 birds from 1988-2006 at five colony sites in Massachusetts, New York, and Connecticut, USA, to examine temporal variation in the survival rates of adult Roseate Terns (Sterna dougallii) during periods of overall population increase (1988-2000) and decline (2000-2006). Roseate Terns nested at only one colony site in Buzzards Bay, Massachusetts at the start of this period, but two more sites in this area were recolonized as the study progressed. Adult survival rates varied temporally in overall population increase (0.835 +/- 0.006 SE) and the period of population decline (0.835 +/- 0.008 SE). As expected based on previous work, adult survival from 1991 to 1992 was lowered as a result of a severe hurricane in August 1991. An oil spill in Buzzards Bay in April 2003 did not appear to result in lower survival of the birds nesting at the variation in other vital rates of this species (such as postfledging survival) needs to be examined to determine the likely cause(s) of the recent population decline.

Waterbirds↗
USGS2004

The adaptive significance of stealing in a marine bird and its relationship to parental quality

Kleptoparasitism (food theft) is a tactic used opportunistically by many foraging birds, but little is known about its fitness benefits. Here we show that habitual kleptoparasitism by individual parent roseate terns (Sterna dougallii) is associated with consistently superior reproductive performance relative to nonkleptoparasitic ('honest') parents, as measured by growth and survival to fledging among their offspring. In broods of two, both chicks of kleptoparasitic parents exhibited superior growth performance during the middle and later stages of the rearing period, relative to chicks of honest parents. This difference was especially pronounced in second-hatched chicks, whose survival is highly variable among years and dependent on food availability. Over a 10-year period, average productivity (number of chicks fledged per pair) was significantly higher among kleptoparasites than among honest parents, with a larger relative difference during years of food shortage. Our study indicates that kleptoparasitism in roseate terns is an important component of parental quality and provides the first evidence that food stealing is associated with enhanced fitness in a facultatively kleptoparasitic seabird.

Behavioral Ecology↗
USGS2004

Detecting warning signs of trouble within population fluctuations: using capture-recapture modeling to uncover changes in population dynamics leading to declines

An intensive mark-recapture/resighting program has been carried out on the Roseate Terns nesting at Falkner Island, Connecticut, since the late 1980s as part of a regional study of the metapopulation dynamics and ecology of the endangered Northwest Atlantic breeding population of this species. Substantial losses of tern eggs and chicks to predation at this colony site began in 1996 when at least five Black-crowned Night-Herons started nocturnal raids. This depredation has been a major factor in the reduction of productivity from an average of about 1.0 chicks/pair for the 10 years before night-heron predation began to as low as about 0.2 chicks/pair in 2002. Recent capture-recapture modelling analyses have detected other important impacts on the population dynamics of the Roseate Terns at this site including a reduction by about half in the 'development-of-residency' rates of first-time breeders, and a substantial decline in the local 'survival-and-fidelity' rates of experienced breeders believed due mostly to increased immigration rates to other colony sites.

Annual Meeting of the Association of Field Ornitho↗
USGS2002

Test for age-specificity in survival of the common tern

Much effort in life-history theory has been addressed to the dependence of life-history traits on age, especially the phenomenon of senescence and its evolution. Although senescent declines in survival are well documented in humans and in domestic and laboratory animals, evidence for their occurrence and importance in wild animal species remains limited and equivocal. Several recent papers have suggested that methodological issues may contribute to this problem, and have encouraged investigators to improve sampling designs and to analyse their data using recently developed approaches to modelling of capture-mark-recapture data. Here we report on a three-year, two-site, mark-recapture study of known-aged common terns (Sterna hirundo) in the north-eastern USA. The study was nested within a long-term ecological study in which large numbers of chicks had been banded in each year for > 25 years. We used a range of models to test the hypothesis of an influence of age on survival probability. We also tested for a possible influence of sex on survival. The cross-sectional design of the study (one year's parameter estimates) avoided the possible confounding of effects of age and time. The study was conducted at a time when one of the study sites was being colonized and numbers were increasing rapidly. We detected two-way movements between the sites and estimated movement probabilities in the year for which they could be modelled. We also obtained limited data on emigration from our study area to more distant sites. We found no evidence that survival depended on either sex or age, except that survival was lower among the youngest birds (ages 2-3 years). Despite the large number of birds included in the study (1599 known-aged birds, 2367 total), confidence limits on estimates of survival probability were wide, especially for the oldest age-classes, so that a slight decline in survival late in life could not have been detected. In addition, the cross-sectional design of this study meant that a decline in survival probability within individuals (actuarial senescence) could have been masked by heterogeneity in survival probability among individuals (mortality selection). This emphasizes the need for the development of modelling tools permitting separation of these two phenomena, valid under field conditions in which the recapture probabilities are less than one.

Book chapter↗
USGS2001

Maternal steroids and contaminants in common tern eggs: A mechanism of endocrine disruption?

We looked for evidence for the hypothesis that exposure of female birds to polychlorinated biphenyls (PCBs) results in alteration of blood steroid hormone concentrations and alters subsequent hormone transfer of steroids to eggs. Eggs of three-egg clutches were collected from a PCB-exposed common tern ( Sterna hirundo ) colony (Ram Island, Buzzards Bay, MA, USA) and from a relatively clean colony (Bodkin Island, Chesapeake Bay, MD, USA), and were analyzed for concentrations of organochlorine contaminants and steroid hormones (17β-estradiol, 5α-dihydrotestosterone, testosterone and androstenedione). There was no relationship between total PCBs and steroid concentrations considering all eggs together, considering eggs of different laying order or considering differences between sequentially laid eggs in a clutch. Similarly, concentrations of di- and tri-chlorinated biphenyls and steroids in eggs were not related. The concentrations of PCBs, mercury and selenium were below estimated thresholds for toxicity to embryos. Maternal steroids, except estradiol, were present in yolk of all eggs, with increasing concentrations in the second and third eggs laid. Our data provided no evidence for a maternal toxicological event that might alter the amount of maternal steroid hormone transferred to eggs.

Comparative Biochemistry and Physiology, Part C: T↗
USGS1999

Predicting chick survival and productivity of Roseate Terns from data on early growth

Early growth of Roseate Tern (Sterna dougallii) chicks is a strong predictor of chick survival and hence of productivity. We developed discriminant functions to predict chick survival from body-masses measured during the first 3 days of life. Productivity is estimated by assuming that almost all A-chicks (first-hatched in each brood) survive to fledging, and using the discriminant functions to predict survival of B-chicks (second-hatched in each brood). A relation between survival rates and classification rates is derived, allowing discriminant function results to be used in predicting survival rates. In the absence of predation, the resulting estimates of chick survival and productivity are almost as good as those obtained by more intensive methods, but require much less effort and much less disturbance. This approach might be useful for other seabird species in which chick survival is determined primarily by parental performance.

Waterbirds↗
USGS1999

Contribution of research to management and recovery of the roseate tern: review of a twelve-year project

The Northwest Atlantic population of the Roseate Tern (Sterna dougallii) is largely confined to a small breeding area along the northeast coast of the USA between 40? and 42?N. This population was listed as endangered in the USA in 1987 because it was dangerously concentrated into a few breeding sites (85% on two islands in the 1980s). The nesting population in the area from Long Island, New York to Cape Cod, Massachusetts has been studied intensively since 1987, in conjunction with a program of management of the breeding colonies. This paper summarizes the results of the research program and discusses the extent to which it has contributed to effective management. The regional population now numbers about 4,000 breeding pairs and has been increasing slowly since 1987, except between 1991 and 1992 when it declined by about 17%. This decline was probably caused by Hurricane `Bob' in August 1991. Roseate Terns have specialized foraging habits and are concentrated into a small number of foraging areas near the nesting colonies. The historically important breeding sites were taken over by large gulls between 1930 and 1972. Many of the terns moved to less suitable sites near the mainland, where they are subject to predation by mainland-based predators. Despite this, Roseate Terns breed with high success at many sites. The sex-ratio is skewed towards females; about 12% of nests are attended by female-female pairs. The annual adult survival rate (0.83) is unusually low for a seabird. Most mortality occurs away from the breeding grounds, but the winter quarters remained unknown until one roost site was found in Brazil in 1995-1997. A major management goal has been to restore former colony-sites by eliminating nesting gulls, but the success of some of these projects has been questionable because they may have attracted birds to sites with higher levels of predation. Although the research has yielded important information about the biology and demography of the species, it has taken longer than expected to obtain and analyze data from multiple sites on this long-lived species. Most work has been carried out at breeding sites: critical studies on feeding ecology and winter ecology have been hampered by insufficient funding and the paucity of self-motivated biologists. Hence, the program has not yet provided all the keys to restoring the population.

Waterbirds↗
USGS1999

A nonbreeding concentration of Roseate and Common Terns in Bahia, Brazil

We report recoveries of banded Roseate (Sterna dougallii) and Common (S. hirundo) Terns netted at Mangue Seco, Bahia, Brazil (11? 27'S, 37? 21'W). Mangue Seco is the first reported South American location where large numbers of Roseate Terns concentrate December-March, and where members of both the North American and Caribbean populations occur together during these months. A Roseate Tern recovered at Mangue Seco sets an age record of 25.6 years for the species. Recoveries at Mangue Seco of Common Terns banded in the Azores (37? -38?N, 25? -29?W) suggest there is a regular transatlantic movement by Common Terns between the two locations.

Journal of Field Ornithology↗
USGS1998

Variations in growth of roseate tern (Sterna dougallii) chicks: II. Early growth as an index of parental quality

We measured growth of Roseate Tern (Sterna dougallii) chicks at a colony in Connecticut in 10 successive years. Data on body mass during the first three to four days of life were fitted to a quadratic regression model, yielding three parameters of early growth for each of 1,551 chicks: mass at hatching (Mo), linear growth (a) and quadratic growth (b). First chicks in each brood (A-chicks) exceeded second chicks (B-chicks) in each of the three growth parameters; A-chicks from broods of two grew faster than single chicks during the first three days. Mo depended on egg mass, hatch order, hatch date, and year. The linear coefficient (a) depended on hatch date, hatch order, and year, but not on egg mass or Mo. The quadratic coefficient (b) depended on a, hatch date, Mo, and hatch order. Subsequent growth and survival of chicks were predicted well by these parameters of early growth, with b contributing more to these predictions than Mo or a. After controlling for effects of early growth, none of the other variables measured (hatch date, egg mass, parental age, hatch interval between chicks, mass difference between chicks, female-female pairing, or trapping) contributed significantly to explaining later growth and survival. Year effects were substantial in only two of the 10 years of study. Individual pairs were consistent in performance (as indexed by chick growth) in successive years. These results suggest that growth and survival of Roseate Tern chicks are determined primarily by parental quality; much of the information about parental quality is expressed by the time the eggs are laid, and most of it is expressed by the time the chicks are three days old.

Condor↗
USGS1995

Colony differences in response to trapping in roseate terns

Both members of seabird pairs are normally required to fledge young. Seabirds that nest in sites accessible to predators usually have one parent in attendance during the egg/chick phase. Time devoted to foraging can vary with individual skill and age, prey availability and abundance (Seamy 1978), and distance to foraging grounds (Safina 1990). Although average skill of similar-aged individuals should not vary from colony to colony (Ryder 1980), prey availability and abundance, and spatial distribution of foraging grounds may vary. Thus, the percent of time both members of a pair are present at the nest site may vary in different colonies. In this paper, we examine parental behavior in response to trapping in Roseate Terns (Sterna dougallii) nesting in three of the six major colonies in the northeastern United States: Cedar Beach, New York, Falkner Island, Connecticut; and Bird Island, Massachusetts. Roseate Terns were listed on the United States? Endangered Species List in 1987. We were interested in differences among colonies in how often both parents were present, how soon a mate returned to the nest if one parent was temporarily removed, how soon a trapped bird returned to the nest after release, and the time during which the nest was left unguarded. We feel it is important to recognize and make management decisions based on colony differences where they exist. Our study follows directly from earlier work at Cedar Beach on trapping vulnerability of Common Terns (Sterna hirundo) and Roseate Terns. Nisbet reported that Roseate Terns at Bird Island required about three hours to return to the nest after trapping.

Condor↗
USGS1994

Sources of variation in loss rates of color bands applied to adult roseate terns ( Sterna dougallii ) in the western North Atlantic

A model-based analysis was done to test several hypotheses concerning the rates of loss of butt-ended color bands placed on adult Roseate Terns ( Sterna dougallii ) in the western North Atlantic. These birds were captured and color banded from 1987-1991 at four colony sites, and recaptured from 1989-1992 as part of a study of the population dynamics of this species. Two types of color bands, Darvic and celluloid, were used, but only one band type was used for each individual bird. Each bird was given three color bands. The estimated probability that a bird with all color bands present during one breeding season still had all color bands during the next breeding season was 0.87. The analysis provided no evidence that colony site, cohort, calendar year of banding, age of color band, or whether or not the bands were heat-sealed closed, were important sources of variation in band-retention probabilities.

The Auk↗
USGS1984

Occurrence and timing of second clutches in common terns

Eighteen pairs of Common Terns (Sterna hirundo) at three different colonies laid second clutches while still feeding young from their first broods. Seven clutches were laid before the chicks from the first brood fledged, and 11 were laid after the chicks from the first brood fledged. In each case, parents alternately fed chicks from the first brood and incubated the second clutch. Sixteen of the 18 clutches disappeared, were addled, or were deserted. Young hatched from the two other second clutches, but all chicks died or disappeared 2-4 days after hatching. We suggest that a second clutch, laid before chicks from the first brood fledged, probably results from a physiological miscue associated with chick loss from the first brood and stimulated by an unusual surplus of food. Conversely, when laid after chicks from the first brood fledge, a second clutch might function as insurance, permitting a pair to raise young late in the season if chicks from the first brood are lost. In either case, parents must partition care between eggs and chicks from the second clutch and fledged chicks from the first brood. Accordingly, the successful fledging of chicks from two broods in a single season is unlikely unless exceptionally favorable conditions occur.

The Auk↗
USGS1983

Organochlorine residues and shell characteristics of roseate tern eggs, 1981

Roseate Terns ( Sterna dougallii ) breed in two areas in the Western Hemisphere: in northeastern North America between Long Island, New York, and Nova Scotia, and around the Caribbean Sea from the Florida Keys and the Bahamas to the Netherlands Lesser Antilles (Bent 1921, Bond 1956, Nisbet 1980). Both populations are small, and concern recently has been expressed about their status (Nisbet 1980, Buckley and Buckley 1981). The northeastern population has decreased from a peak of about 8500 pairs in the 1940s to between 2500 and 3000 pairs in 1978-1982, and has become largely concentrated into 4 colonies (Nisbet 1980). The Caribbean population has been affected by egg collecting and other forms of human disturbance in its main stronghold in the U.S. Virgin Islands (U.S. Virgin Islands Bureau of Fish and Wildlife 1976-1979, Norton 1980, 1981). One factor which may have affected the northeastern population is chemical pollution. Hays and Risebrough (1972) reported high levels of polychlorinated biphenyls (PCBs) and l,l-dichloro-2,2-bis(p-chloro phenyl) ethylene (DDE) in 3 Roseate Tern chicks found with congenital abnormalities at Great Gull Island, New York, in 1970. High levels of PCBs were also found in chicks found dead at Bird Island, Massachusetts, in 1970 (Nisbet 1981). A close relative, the Common Tern ( S. hirundo ), is relatively sensitive to the effects of DDE; elevated residues of DDE in eggs are associated with eggshell-thinning (Switzer et al. 1973), reduction in the porosity of eggshells, and embryonic mortality (Fox 1976). The present paper reports the results of a survey of organochlorine residues in Roseate Terns in 1981. The main objectives of the survey were to determine the levels of organochlorine contamination in eggs of the Roseate Tern in its major colonies and to investigate whether changes in eggshell characteristics similar to those reported by Fox (1976) may have occurred in this species. A secondary objective was to determine geographic patterns of organochlorine contamination within the northeastern U.S. population of Roseate Terns and to compare them with patterns observed in Common Terns

Connecticut, Massachusetts, New York↗