Colored plastic and metal leg bands do not affect survival of Piping Plover chicks

ABSTRACT Leg bands are commonly used to mark shorebird chicks as young as 1‐d old, but little is known about the possible impacts of bands on survival of prefledging shorebirds. We used a mark‐recapture framework to assess the impact of bands and banding‐related disturbance on prefledging survival in a federally endangered population of Piping Plovers (Charadrius melodus) breeding in the Great Lakes region from 2000 to 2008. We banded approximately 96% of all surviving chicks hatched prior to fledging, typically between 5 and 15 d of age. We used a multistate approach in program MARK whereby individuals contributed data as unbanded chicks before capture (N= 1073) and as banded chicks afterward (N= 780). The cumulative probability of surviving through 24 d of age was 0.63 and did not differ between banded and unbanded chicks. In addition, we found a positive effect of banding‐related disturbance on survival up to 3 d following banding (β= 0.60 CI: 0.17–1.02), possibly due to increased postbanding vigilance on the part of chicks and adults. Our results indicate that banding has no detrimental effect on survival of Piping Plover chicks prior to fledging and that current capture and banding methods are appropriate for this endangered species.     

Facultative and non‐facultative sex ratio adjustments in a dimorphic bird species

If parental allocation to each offspring sex has the same cost/benefit ratio, Fisher's hypothesis predicts a sex ratio biased towards the cheaper sex. However, in dimorphic birds there is little evidence for this, especially at hatching. We investigated the pre‐fledgling 1) sex ratio, 2) body condition and 3) sex‐differential mortality in a population of the glossy ibis Plegadis falcinellus, in southern Spain between 2001 and 2011. We defined two age groups for the period between hatching and fledging. We also compared pre‐fledgling with the autumn sex ratio. Metabolic rates were estimated by the doubly labeled water (DLW) technique to establish that sons (the bigger sex) were 18% more energy demanding than daughters, and to compute the predicted Fisher's sex ratio (0.465). As population size increased between years, body condition decreased in both sexes, and mortality increased more for daughters than sons prior to fledging. At the same time, the proportion of males among chicks close to fledging increased (average sex ratio: 0.606) while the proportion close to hatching decreased (average sex ratio: 0.434, in line with Fisher's prediction). Furthermore, the proportions of males at fledging and the following autumn were negatively correlated across years. We suggest that, as population density increased and conditions worsened the larger sex had relatively higher survival. These differences in survival produce a shift from a facultative female‐biased sex ratio at hatching into a non‐facultative male‐biased sex ratio of fledglings. Additionally, the excess of males at fledging was counterbalanced by sex‐related dispersal during the autumn. Overall, glossy ibis sex ratio is a product of a combination of facultative and non‐facultative adjustments triggered by environmental conditions, driven by rapid population growth, and mediated by highly interrelated life‐history traits such as body condition, mortality, and dispersal.     

Relationship of current management practices to movements of Piping Plover broods in an Atlantic Coast population

Mobility of precocial chicks facilitates self-feeding and escape from predators, but also allows chicks to move into potentially dangerous areas. At Cape Hatteras National Seashore and Pea Island National Wildlife Refuge, North Carolina, precocial Piping Plovers (Charadrius melodus) are managed with vehicle and pedestrian exclusion buffers to reduce potential anthropogenic disturbance and mortality. From 2015 to 2018, we monitored 23 broods from hatching until fledging age (25 days), and recorded brood locations, chick behavior, and potentially disruptive predators, people, or vehicles. We estimated straight-line hourly movement rates relative to brood habitat selection, behavior, and potential disturbance stimuli, daily movement distances, and 95% minimum convex polygon home range areas of broods through the pre-fledging period. Daily brood movements , range = 0–327.3 m/d) varied by age and year. Hourly movements also varied , range = 0.04–1450.9 m/h), but were not well described by the factors we tested. Daily and hourly movements were generally shorter than current management buffer sizes, broods were always observed within protective buffers, and were rarely disturbed by human activity or possible predators. Home range sizes of broods ( increased as broods aged. Our results show that movements by plover broods can be variable and relatively unpredictable across temporal and spatial scales, but the low rate of brood disturbance suggests effective management of anthropogenic disturbance. We recommend that under current conditions, regular monitoring by managers should continue to ensure that the size and location of implemented buffers track actual brood use without exposing broods to risks from human beach users.     

Age‐specific survival and recruitment of piping plovers Charadrius melodus in the Great Lakes region

Juvenile survival and age at first breeding (i.e. recruitment) are critical parameters affecting population dynamics in birds, but high levels of natal dispersal preclude measurement of these variables in most species. We used multi‐state capture–recapture models to measure age‐specific survival and recruitment probabilities of piping plovers Charadrius melodus in the Great Lakes region during 1993–2012. This federally endangered population is thoroughly monitored throughout its entire breeding range, minimizing concerns that measures of survival and recruitment are confounded by temporary or permanent emigration. First‐year survival (± SE) averaged 0.284 ± 0.019 from mean banding age (9 d) and 0.374 ± 0.023 from fledging age (23 d). Factors that increased first‐year survival during the pre‐fledging period (9–23 d) included earlier hatching dates, older age at banding, greater number of fledglings at a given site, and better body condition at time of banding. However, when chicks that died prior to fledging were excluded from analysis, only earlier hatching dates improved first‐year survival estimates. Females had a higher probability (0.557 ± 0.066) of initiating breeding at age one than did males (0.353 ± 0.052), but virtually all plovers began breeding by age three. Adult survival was reduced by increased hurricane activity on the southeast U.S. Atlantic coast where Great Lakes piping plovers winter and by higher populations of merlins Falco columbarius. Mean annual adult survival declined from 1993 to 2012, and did not differ between males and females. Enhanced body condition led to higher survival to fledge and early breeding led to improved first‐year survival; therefore, management actions focused on ensuring access to quality feeding habitat for growing young and protecting early nests may increase recruitment in this federally endangered population.     

Ontogenic differences in sexual size dimorphism across four plover populations

Sexual size dimorphism (SSD) among adults is commonly observed in animals and is considered to be adaptive. However, the ontogenic emergence of SSD, i.e. the timing of divergence in body size between males and females, has only recently received attention. It is widely acknowledged that the ontogeny of SSD may differ between species, but it remains unclear how variable the ontogeny of SSD is within species. Kentish Plovers Charadrius alexandrinus and Snowy Plovers C. nivosus are closely related wader species that exhibit similar, moderate (c. 4%), male‐biased adult SSD. To assess when SSD emerges we recorded tarsus length variation among 759 offspring in four populations of these species. Tarsus length of chicks was measured on the day of hatching and up to three times on recapture before fledging. In one population (Mexico, Snowy Plovers), males and females differed in size from the day of hatching, whereas growth rates differed between the sexes in two populations (Turkey and United Arab Emirates, both Kentish Plovers). In contrast, a fourth population (Cape Verde, Kentish Plovers) showed no significant SSD in juveniles. Our results suggest that adult SSD can emerge at different stages of development (prenatal, postnatal and post‐juvenile) in different populations of the same species. We discuss the proximate mechanisms that may underlie these developmental differences.     

Sons do not take advantage of a head start: parity in herring gull offspring sex ratios despite greater initial investment in males

Skewed adult sex ratios sometimes occur in populations of free‐living animals yet the proximate mechanisms, timing of sex‐biases, and the selective agents contributing to skew remain a source of debate with contradictory evidence from different systems. We investigated potential mechanisms contributing to sex biases in a population of herring gulls with an apparent female skew in the adult population. Theory predicts that skewed adult sex ratios will adaptively lead to skewed offspring sex ratios to restore balance in the effective breeding population. Parents may also adaptively bias offspring sex ratios to increase their own fitness in response to environmental factors. Therefore, we expected to detect skewed sex ratios either at hatching or at fledging as parents invest differentially in offspring of different sexes. We sampled complete clutches (n = 336 chicks) at hatching to quantify potential skews in sex ratios by position in the hatch order, time of season, year, and nesting context (nest density), finding no departure from equal sex ratios at hatching related to any of these factors. Further, we sampled 258 chicks at near‐fledging to investigate potential sex biases in survival at the chick stage. Again, no biases in sex ratios were recorded. Male offspring were favored in this population via greater maternal investment in eggs carrying male embryos and greater parental provisioning of male offspring which reached greater sizes by fledging. Despite the advantages realized by male offspring, females were equally as likely to fledge as males. Thus, biased adult sex ratios apparently arise in the post‐fledging and pre‐recruitment stage in our population.     

Variably male-biased sex ratio in a marine bird with females larger than males

When the costs of rearing males and females differ progeny sex ratios are expected to be biased toward the less expensive sex. Blue-footed booby (Sula nebouxii) females are larger and roughly 32% heavier than males, thus presumably more costly to rear. We recorded hatching and fledging sex ratios in 1989, and fledging sex ratios during the next 5 years. In 1989, the sample of 751 chicks showed male bias at hatching (56%) and at fledging (57% at ˜90 days). Fledging sex ratios during the five subsequent reproductive seasons were at unity (1 year) or male-biased, varying from 56% to 70%. Male bias was greater during years when mean sea surface temperature was warmer and food was presumably in short supply. During two warm-water years (only) fledging sex ratio varied with hatching date. Proportions of male fledglings increased with date from 0.48 to 0.73 in 1994, and from 0.33 to 0.79 in 1995. Similar results were obtained when the analysis was repeated using only broods with no nestling mortality, suggesting that the overall increase in the proportion of males over the season was the result of sex ratio adjustments at hatching. The male-biased sex ratio, and the increased male bias during poor breeding conditions supports the idea that daughters may be more costly than sons, and that their relative cost increases in poor conditions. Received: 3 February 1998 / Accepted: 12 September 1998     

Survival,site fidelity,and the population dynamics of Piping Plovers in Saskatchewan

ABSTRACT To conserve threatened species, managers require predictions about the effects of natural and anthropogenic factors on population growth that in turn require accurate estimates of survival, birth, and dispersal rates, and their correlation with natural and anthropogenic factors. For Piping Plovers (Charadrius melodus), fledging rate is often more amenable to management than adult survival, and population models can be used to estimate the productivity (young produced per breeding female) necessary to maintain or increase populations for given levels of survival. We estimated true survival and site fidelity of adult and subadult (from fledging to second year) Piping Plovers breeding in Saskatchewan using mark‐resight data from 2002 to 2009. By estimating true survival rather than apparent survival (which is confounded with permanent emigration), we were able to provide more accurate projections of population trends. Average adult and subadult survival rates during our study were 0.80 and 0.57, respectively. Adult survival declined over time, possibly due in part to the loss of one breeding site to flooding. Average adult and subadult site fidelity were 0.86 and 0.46, respectively. Adult site fidelity declined during our study at two study sites, most strongly at the flooded site. Male and female Piping Plovers had similar survival rates, but males had greater site fidelity than females in some years. Based on our survival estimates, productivity needed for a stationary population was 0.75, a benchmark used for plover management on the Atlantic Coast, but not previously estimated for Prairie Canada. In stochastic simulations incorporating literature‐based variation in survival rates, productivity needed for a stationary population increased to 0.86, still lower than that previously estimated for western populations. Mean productivity for our study sites ranged from 0.87 to 0.96 fledged young per pair. Our results suggest that fledging rates of Piping Plovers in Saskatchewan were sufficient to ensure a stationary or increasing population during our study period. However, large‐scale habitat changes such as drought or anthropogenic flooding may lead to dispersal of breeding adults and possibly mortality that will increase the fledging rate needed for a stationary population.     

Prebreeding survival of Roseate Terns Sterna dougallii varies with sex,hatching order and hatching date

Unequal sex ratios can reduce the productivity of animal populations and are especially prevalent among endangered species. A cohort of 333 Roseate Tern Sterna dougallii chicks at a site where the adult sex ratio was skewed towards females was sexed at hatching and followed through fledging and return to the breeding area, and subsequently during adulthood. The entire regional metapopulation was sampled for returning birds. Prebreeding survival (from fledging to age 3 years) was lower in males than in females, but only among B‐chicks (second in hatching order). Prebreeding survival also declined with hatching date. The proportion of females in this cohort increased from 54.6% at hatching to 56.2% at fledging and to an estimated 58.0% among survivors at age 3 years. This was more than sufficient to explain the degree of skew in the sex ratio of the adult population, but changes in this degree of skew during the study period make it difficult to identify the influence of a single cohort of recruits. Many studies of prebreeding survival in other bird species have identified effects of sex, hatching order or hatching date, but no previous study has tested for effects of all three factors simultaneously.     

Sexual dimorphism,survival, and parental investment in relation to offspring sex in a precocial bird

Differential growth rate between males and females, owing to a sexual size dimorphism, has been proposed as a mechanism driving sex‐biased survival. How parents respond to this selection pressure through sex ratio manipulation and sex‐biased parental investment can have a dramatic influence on fitness. We determined how differential growth rates during early life resulting from sexual size dimorphism affected survival of young and how parents may respond in a precocial bird, the black brant Branta bernicla nigricans. We hypothesized that more rapidly growing male goslings would suffer greater mortality than females during brood rearing and that parents would respond to this by manipulating their primary sex ratio and parental investment. Male brant goslings suffered a 19.5% reduction in survival relative to female goslings and, based on simulation, we determined that a female biased population sex ratio at fledging was never overcome even though previous work demonstrated a slight male‐biased post‐fledging survival rate. Contrary to the Fisherian sex ratio adjustment hypothesis we found that individual adult female brant did not manipulate their primary sex ratio (50.39% male, n = 645), in response to the sex‐biased population level sex ratio. However, female condition at the start of the parental care period was a good predictor of their primary sex ratio. Finally, we examined how females changed their behavior in response to primary sex ratio of their broods. We hypothesized that parents would take male biased broods to areas with increased growth rates. Parents with male biased primary sex ratios took broods to areas with higher growth rates. These factors together suggest that sex‐biased growth rates during early life can dramatically affect population dynamics through sex‐biased survival and recruitment which in turn affects decisions parents make about sex allocation and sex‐biased parental investment in offspring to maximize fitness.     

The influence of sex and body size on nestling survival and recruitment in the house sparrow

Differences in the survival rates of males and females over the period from hatching to recruitment can have important impacts on individual fitness and population demographics. However, whilst the influence of an individual's sex on nestling growth and survival has been well studied, less is known about sex‐specific survival over the period between fledging and recruitment. Here, we analyse nestling survival and recruitment in an isolated, island population of house sparrows (Passer domesticus), using data collected over a 4‐year period. Nestlings that had a greater mass at 1 day old were more likely to fledge. Recruitment was also positively associated with day 11 mass. The positive influence of nestling mass on survival to fledging also increased as brood size increased. There was no difference in the survival of male and female individuals prior to fledging. In contrast, over the period from fledging to recruitment, females had significantly less mortality than males. Recruitment was also positively associated with 11‐day‐old mass. Neither the nestling sex ratio nor the fledging sex ratio deviated from 0.5, but the sex ratio amongst recruits was female biased. Our study shows that sex can influence juvenile survival, but also shows that its effect varies between different life‐history stages; therefore, these stages should be considered separately if we want to understand at what point sex‐specific differences in juvenile survival occur. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 680–688.     

Unusual pattern of sex‐specific mortality in relation to initial brood sex composition in the black‐billed magpie Pica pica

In sexually size‐dimorphic species, brood sex composition may exert differential effects on sex‐specific mortality. We investigated the sex‐specific mortality and body condition in relation to brood sex composition in nestlings of the black‐billed magpie Pica pica. Neither significantly sex‐biased production at hatching nor overall sex‐biased mortality during the nestling period was found. Sex‐specific mortality as a function of brood sex composition, however, differed between female and male nestlings. We found higher mortality for females in male‐biased broods and higher mortality for males in female‐biased broods, a phenomenon that we call ‘rarer‐sex disadvantage’. As a result, fledging sex ratios became more biased in the direction of bias at hatching, a phenomenon that cannot be readily explained by previous hypotheses for sex‐specific mortality. Two temporal variables, fledging date and laying date, were also correlated with sex‐specific mortality: female nestlings in earlier broods experienced higher mortality than male nestlings whereas male nestlings in later broods experienced higher mortality. We suggest that this unusual pattern of mortality may be explained by adaptive adjustments of brood sex composition by parents, either through the effects of a slight sex difference in offspring dispersal patterns on parental fitness, or owing to sex differences as regards the benefits of early fledging.     

Sex allocation and sex‐specific parental investment in an endangered seabird

Biased offspring sex ratio is relatively rare in birds and sex allocation can vary with environmental conditions, with the larger and more costly sex, which can be either the male or female depending on species, favoured during high food availability. Sex‐specific parental investment may lead to biased mortality and, coupled with unequal production of one sex, may result in biased adult sex ratio, with potential grave consequences on population stability. The African Penguin Spheniscus demersus, endemic to southern Africa, is an endangered monogamous seabird with bi‐parental care. Female adult African Penguins are smaller, have a higher foraging effort when breeding and higher mortality compared with adult males. In 2015, a year in which environmental conditions were favourable for breeding, African Penguin chick production on Bird Island, Algoa Bay, South Africa, was skewed towards males (1.5 males to 1 female). Males also had higher growth rates and fledging mass than females, with potentially higher post‐fledging survival. Female, but not male, parents had higher foraging effort and lower body condition with increasing number of male chicks in their brood, thereby revealing flexibility in their parental strategy, but also the costs of their investment in their current brood. The combination of male‐biased chick production and higher female mortality, possibly at the juvenile stage as a result of lower parental investment in female chicks, and/or at the adult stage as a result of higher parental investment, may contribute to a biased adult sex ratio (ASR) in this species. While further research during years of contrasting food availability is needed to confirm this trend, populations with male‐skewed ASRs have higher extinction risks and conservation strategies aiming to benefit female African Penguin might need to be developed.     

Male‐skewed adult sex ratio,survival, mating opportunity and annual productivity in the Snowy Plover Charadrius alexandrinus

Sex differences in adult mortality may be responsible for male‐skewed adult sex ratios and male‐skewed parental care in some birds. Because a surplus of breeding males has been reported in serially polyandrous populations of Snowy Plover Charadrius alexandrinus, we examined sex ratio, early‐season nesting opportunities, adult survival and annual reproductive success of a Snowy Plover population at Monterey Bay, California. We tested the hypotheses that male adult survival was greater than female survival and that a sex difference in adult survival led to a skewed adult sex ratio, different mating opportunities and different annual productivity between the sexes. Virtually all females left chicks from their first broods to the care of the male and re‐nested with a new mate. As a result, females had time to parent three successful nesting attempts during the lengthy breeding season, whereas males had time for only two successful attempts. Among years, the median population of nesting Plovers was 96 males and 84 females (median difference = 9), resulting in one extra male per eight pairs. The number of potential breeders without mates during the early nesting period each year was higher in males than in females. Adult male survival (0.734 ± 0.028 se) was higher than female survival (0.693 ± 0.030 se) in top‐ranked models. Annually, females parented more successful clutches and fledged more chicks than their first mates of the season. Our results suggest that in C. alexandrinus a sex difference in adult survival results in a male‐skewed sex ratio, which creates more nesting opportunities and greater annual productivity for females than for males.     

Ontogeny of chick behavior: a tool for monitoring the growth and development of lesser adjutant storks

We studied the behavioral development of seven lesser adjutant stork (Leptoptilos javanicus) chicks from hatching to fledging over three breeding seasons at the Bronx Zoo. We developed an ethogram and compared the rate at which behaviors appeared in relation to brood size, sex, and the conditions in which the chicks were raised by their parents. Although sample sizes were small, there seem to be sex‐related differences in the rate at which behaviors develop, with females developing more rapidly than males. Larger clutch size may be associated with slower growth rate because the single male developed faster than the two males in 2004. The slowest growth rate, observed in a single male chick in 1999, was most likely owing to nutritional deficiencies and other health complications. More research is needed, but these results can be used to help evaluate the age and health of lesser adjutant stork chicks in captivity and in the wild. Zoo Biol 26:533–538, 2007. © 2007 Wiley‐Liss, Inc.     

Sex-biases in the hatching sequence of cooperatively breeding apostlebirds <Emphasis Type="Italic">Struthidea cinerea</Emphasis>

In the cooperatively breeding apostlebird (Struthidea cinerea, Corcoracidae) both sexes are philopatric and help to raise offspring. However, male helpers provision nestlings more often than females, an activity associated with reduced nestling starvation and enhanced fledgling production. Presuming that males are the more helpful sex, we examined the helper repayment hypothesis by testing the predictions that offspring sex ratio should be skewed toward the production of males (a) among breeding groups with relatively few helpers, and (b) in the population as a whole. The relationship between sex and hatching order was examined as a potential mechanism of biasing sex allocation. The sex ratio of all sexed offspring was male biased (57.9%; n = 171) as was the mean brood sex ratio (0.579; n = 70 broods). These biases were less pronounced in the subset of clutches/broods in which all offspring were sexed. This overall bias appeared to result from two distinct patterns of skew in the hatching order. First, mothers in small breeding groups produced significantly more males among the first-hatching pair. This is consistent with the helper repayment hypothesis given that later hatching chicks were less likely to survive, particularly in small groups. Second, almost all fourth-hatching chicks, usually the last in the brood, were male (91.7%, n = 12). This bias is difficult to interpret but demonstrates the value of examining hatching sequences when evaluating specific predictions of sex allocation theory in birds.     

Effect of capture frequency on the survival of Piping Plover chicks

Evaluating the possible effects of intensive research on species being studied and on the results of studies is important for both ethical and scientific reasons. We captured, banded, recaptured, and measured prefledged Piping Plover (Charadrius melodus) chicks during the 2010 breeding season at Lewis and Clark Lake on the Missouri River in South Dakota. We evaluated the potential for increased mortality related to frequent handling of chicks with an experiment that compared the survival of chicks handled a single time for banding (N = 48) to chicks handled repeatedly from hatch to fledge (N = 50). Estimates of daily survival rate (?) for chicks in the two treatments did not differ (?_{single‐capture} = 0.984 ± 0.006, ?_{multiple‐capture} = 0.985 ± 0.006). Similar to previous studies, we found little evidence of increased prefledge mortality associated with frequent handling of Piping Plover chicks. However, because the effects of frequent handling of shorebird chicks may vary among species and other factors such as habitat quality (e.g., food availability), we suggest that, where possible, researchers include experiments similar to ours to evaluate possible research impacts, especially when studying threatened and endangered species.     

Exclusion of ground predators improves Northern Lapwing Vanellus vanellus chick survival

Many farmland‐breeding wader species have declined across Europe, probably due to reductions in reproductive output caused by high nest losses as a result of agriculture or predation, or low chick survival between hatching and fledging. Most studies have focused on nest failures, and the factors affecting post‐hatching survival of chicks are poorly known. In an experimental approach, we fenced parts of the arable foraging areas of Northern Lapwing Vanellus vanellus families to quantify chick survival simultaneously in the presence and absence of ground predators. Lapwing chicks were radiotagged to estimate survival probabilities by daily locations, applying multistate capture–recapture models. During the night, chick survival was considerably lower outside fenced plots than within. During the day, chick survival was higher than at night and did not differ between protected and unprotected plots. This suggests that nocturnal ground predators such as Red Foxes Vulpes vulpes were responsible for a significant proportion of chick mortality. Cumulative survival probability from hatching to fledging was 0.24 in chicks within fenced plots, but virtually zero in chicks outside fenced plots. In farmland, temporary electric fences can be effective in minimizing the impact of ground predators and offer a promising short‐term method to increase fledging success of precocial birds.     

Effects of water discharge on fledging time,growth, and survival of piping plovers on the Missouri River

River flow management and modification is a global issue, and its effects on river-dependent organisms are pervasive. Flow modification can directly affect avian species through mortality or habitat loss, but less is known about indirect and sublethal effects of flow modification on reproductive output in these species. Young birds are more vulnerable to predation between hatching and fledging than after flight is achieved, but tradeoffs must be made to balance growth and survival. Predation pressure appears to be a significant factor affecting the time to fledging in altricial birds, but less is known about this threat for precocial birds. Birds reaching fledging earlier should have greater rates of survival to migration because their predator escape repertoire includes flight at an earlier age. We evaluated the effect of varying outflows from the Gavins Point Dam on the growth, age at fledging, and survival of piping plover (Charadrius melodus) chicks on the Missouri River (2006–2009). The study was characterized by 2 relatively high flow years (2006 and 2009) and 2 relatively low flow years (2007 and 2008). We used success rate in recapturing chicks in capture–mark–recapture models as an index for fledging. We attempted to recapture all chicks (n = 1,099) by hand every 3–4 days throughout the season to acquire morphological measurements. Models indicated that as flows from the dam increased, age at fledging increased. We also found that increasing flows were associated with decreasing daily survival rates (β_flow = −2.401, 95% CI: −4.351 to −0.452). Flow was also negatively related to chick mass gain, but we found less evidence for an effect on wing-chord length. Increased flows covered wet-substrate foraging habitat, and likely affected plover reproductive output directly through chick survival and indirectly through decreased growth and increased fledging times. © The Wildlife Society, 2013     

Breeding sites and winter site fidelity of Piping Plovers wintering in The Bahamas,a previously unknown major wintering area

Most of the known wintering areas of Piping Plovers (Charadrius melodus) are along the Atlantic and Gulf coasts of the United States and into Mexico, and in the Caribbean. However, 1066 threatened/endangered Piping Plovers were recently found wintering in The Bahamas, an area not previously known to be important for the species. Although representing about 27% of the birds counted during the 2011 International Piping Plover Winter Census, the location of their breeding site(s) was unknown. Thus, our objectives were to determine the location(s) of their breeding site(s) using molecular markers and by tracking banded individuals, identify spring and fall staging sites, and examine site fidelity and survival. We captured and color‐banded 57 birds in January and February 2010 in The Bahamas. Blood samples were also collected for genetic evaluation of the likely subspecies wintering in The Bahamas. Band re‐sightings and DNA analysis revealed that at least 95% of the Piping Plovers wintering in The Bahamas originated on the Atlantic coast of the United States and Canada. Re‐sightings of birds banded in The Bahamas spanned the breeding distribution of the species along the Atlantic coast from Newfoundland to North Carolina. Site fidelity to breeding and wintering sites was high (88–100%). Spring and fall staging sites were located along the Atlantic coast of the United States, with marked birds concentrating in the Carolinas. Our estimate of true survival for the marked birds was 0.71 (95% CI: 0.61–0.80). Our results indicate that more than one third of the Piping Plover population that breeds along the Atlantic coast winters in The Bahamas. By determining the importance of The Bahamas to the Atlantic subspecies of Piping Plovers, future conservation efforts for these populations can be better focused on where they are most needed.