Charadrius Alexandrinus Research Articles

Distribution and abundance of Snowy Plovers in eastern North America, the Caribbean, and the Bahamas

Abstract Snowy Plovers (Charadrius alexandrinus) are small, partially migrant shorebirds that are broadly distributed across North America. Snowy Plover distribution west of the Rocky Mountains has been well described. However, distribution and abundance east of the Rocky Mountains has not received much attention despite current status and ESA listing concerns for Snowy Plovers in the southeastern United States and the Caribbean. Thus, a first step in developing a monitoring program for Snowy Plovers is to understand the species' distribution. We summarize information on distribution and abundance of Snowy Plovers in the eastern United States, Caribbean, and Bahamas. Breeding and winter distribution maps for the continental United States were generated from a database of 3563 records from 388 sites in continental North America constructed from International Shorebird Survey (ISS), Christmas Bird Count (CBC), unpublished field data, and published accounts. Comparison of maximum counts per site (1980–presen...

Helminth parasites in six species of shorebirds (Charadrii) from the coast of Belize.

Thirteen species of helminth parasites were recovered from six species of charadriid shorebirds (Aves: Charadriiformes) from Belize: the ruddy turnstone, Arenaria interpres, the snowy plover, Charadrius alexandrinus, the semipalmated plover, C. semipalmatus, the killdeer, C. vociferus, the white-rumped sandpiper, Calidris fuscicollis, and the black-bellied plover, Pluvialis squatarola. Cestode species were predominant (N = 8), followed by trematode species (N = 3) and acanthocephala (N = 2). The trematode, Paramaritremopsis solielangi infected four of the six species of hosts. The cestodes, Nadejdolepis litoralis and N. paranitidulans infected three and two host species respectively. Helminth parasite species were contagious (clumped) and not evenly distributed among hosts. Twelve of the 13 species were generalists. The one specialist Microphallus kinsellae was recovered from one C. fuscicollis. Three of the four types of feeding guilds were present and in approximately the same number. All but M. kinsellae have been reported from other species of hosts, mostly from Eurasia and North America.

Susceptibility of Avian Hosts to ExperimentalGymnophalloides seoiInfection

To determine whether avian species are susceptible to infection with Gymnophalloides seoi (a human-infecting intestinal trematode), we exposed 7 species of birds with metacercariae obtained from oysters. The birds were necropsied at days 2, 4, and 6 postinfection (PI). The highest worm recovery at day 6 PI was obtained from the Kentish plover (Charadrius alexandrinus; mean = 56.0%), followed by the Mongolian plover (C. mongolus; 49.3%), and the grey plover (Pluvialis squatarola; 32.3%). In contrast, no mature worms were recovered from the great knot (Calidris tenuirostris), dunlin (C. alpina), black-tailed gull (Larus crassirostris), and mallard (Anas platyrhynchos). Among the plovers, the worms attained the greatest size at day 6 PI (254.1 x 190.4 microm) in the Kentish plover, with a significantly higher number of eggs in the uterus. The 3 species of plovers are highly susceptible to experimental G. seoi infection, suggesting that they could play a role as definitive hosts for these worms in nature.

Inventory and conservation of breeding waterbirds at Ojo de Liebre and Guerrero Negro lagoons, Baja California Sur Mexico

Surveys made in 1997/98 at the lagoons of Ojo de Liebre (Scammon´ s Lagoon) and Guerrero Negro, Baja California Sur, Mexico, showed that changes have occurred since 1926 in the species composition of the community of breeding waterbirds, in the arrangement of their nesting substrate and in their population size. Of 17 species breeding in the area in 1926, we found 12 nesting there during our survey. Additional data from other researchers allowed us to conclude that 16 species have nested in the area after 1984. Only one species (Sterna elegans) has not been reported nesting; however, it is still considered to be a local breeder. Three species (Egretta alba, Larus atricilla and Falco peregrinus) became new established breeders. Most of the species that breed on the islands within Scammon´ s Lagoon have a stable population or have increased in number. None of the egret species breeding in 1926 in marshes outside the islands currently nest there. Four species (Sterna antillarum, Charadrius wilsonia, Charadrius alexandrinus and Rallus longirostris) breed on the islands or at other sites in the lagoons and vicinity. Despite development in the region, the natural wetlands and open-water coverage remain almost unchanged. Natural nesting substrates are mostly confined to the islands and are vulnerable to land predators, wave erosion and direct human disturbance. These factors may have caused the shifting of nesting spots from one island to another and to other suitable nesting sites on the lagoons, the urban landscape, the saltworks and man-made structures. Breeding waterbirds have been granted limited protection through reserves and single-species conservation programs. We suggest guidelines to enhance their protection as a community in the context of El Vizcaíno Biosphere Reserve.

Emergency Restoration for the Western Snowy Plover Following the New Carissa Spill1

ABSTRACT Emergency restoration measures for the western snowy plover (Charadrius alexandrinus nivosus) were implemented during 1999 by the natural resource trustees and the responsible party in response to the M/V New Carissa oil spill near Coos Bay on the Oregon coast. Measures included public education, increased law enforcement, plover nest protection, predator control, and snowy plover habitat creation. An evaluation of the measures indicated that these actions may have contributed to a productive breeding year for the plovers. Potential benefits and rish associated with conducting emergency restoration are discussed. Overall, the authors believe that in certain circumstances, there can be both resource and financial incentives in taking immediate restorative actions where resources are threatened with damage from an oil spill.

Habitat Characteristics and Nest Success of Snowy Plovers Associated with California Least Tern Colonies

Nest success of Snowy Plovers (Charadrius alexandrinus) was estimated at six sites in San Diego County, California, to determine the effects of habitat characteristics and social factors on predation risk. Egg predation was expected to be lower for plovers nesting among Least Terns (Sterna antillarum) because of benefits associated with nesting under the “protective umbrella” of a colonial species. Snowy Plovers nested adjacent to objects and in areas with more vegetation cover than random sites in beach and fill habitats and in areas with more debris cover in beach and salt pan habitats. Estimated nest success from 1994–1997 was 50%, and most predation was attributed to corvids, primarily Common Ravens (Corvus corax). Social factors, including distance to nearest Least Tern and Snowy Plover nests, predicted nest success whereas habitat characteristics did not. Nest success was greatest for plovers nesting closest to an active tern nest and nesting at intermediate distances to conspecifics. Nest success also varied among years and sites, with two sites consistently less successful over the four years. Nests within tern colonies received some mitigation of egg predation. Plover nests initiated prior to the arrival of Least Terns were less likely to hatch eggs than later nests; nevertheless, Snowy Plovers in southern California initiated nesting well before Least Terns. Características del Hábitat y Éxito de la Nidada de Charadrius alexandrinus Asociados a Colonias de Sterna antillarum Resumen. Para determinar los efectos de las características del hábitat y factores sociales sobre el riesgo de depredación, estimé el éxito de las nidadas de Charadrius alexandrinus en seis sitios del Condado de San Diego, California. Se esperaba que la depredación de huevos fuera menor para los C. alexandrinus que anidan junto a Sterna antillarum debido a los beneficios de anidar bajo un “paraguas protector” de una especie colonial. En playas y hábitats rellenados, C. alexandrinus anidó con mayor frecuencia en lugares adyacentes a objetos y en áreas con mayor cobertura de vegetación que en sitios aleatorios y en áreas con mayor cobertura de desechos vegetales en playas y salinas. El éxito estimado de las nidadas entre 1994–1997 fue de 50%, y la mayor tasa de depredación fue atribuida a córvidos, principalmente a la especie Corvus corax. Factores sociales como distancia al nido más cercano de S. antillarum y C. alexandrinus predijeron el éxito de la nidada, mientras que las características del hábitat no lo hicieron. El éxito de la nidada fue mayor para los individuos de C. alexandrinus que nidificaron más cerca de un nido activo de S. antillarum y que nidificaron a distancias intermedias de conespecíficos. El éxito de la nidada también varió entre años y sitios. Dos sitios presentaron consistentemente un menor éxito durante los cuatro años de estudio. Los nidos ubicados dentro de la colonia presentaron una leve disminución en la depredación de huevos. Los huevos de nidos de C. alexandrinus iniciados antes de la llegada de S. antillarum tuvieron una menor probabilidad de eclosión que huevos de nidos más tardíos. Sin embargo, C. alexandrinus comenzó a nidificar bastante antes que S. antillarum en California del Sur.

Intraclutch egg‐size variation and offspring survival in the Kentish Plover Charadrius alexandrinus

We studied the consequences of intraclutch egg‐size variation in Kentish Plovers Charadrius alexandrinus in southern Spain to test the hypothesis that females allocate resources preferentially to eggs with the greatest survival potential. Second eggs were larger and had a greater hatching success than the other eggs in a clutch. However, we did not find unequivocal support for the differential allocation hypothesis, because egg failures according to laying order were not due to the causes predicted by the hypothesis, and the change in egg‐size with laying order was not consistent between successive clutches of renesting females. This suggests that nutrient availability during egg formation could act as a proximate factor affecting egg‐size independently of laying order. Larger eggs produced heavier chicks and, within broods, heavier chicks were most likely to be recruited into the breeding population. By laying clutches with a larger mean egg volume in replacement clutches, females took longer to lay again after failure of the first clutch. Thus, opposing selective forces may act to increase and decrease egg volume. Although a trade‐off between egg‐size and clutch‐size has not been found in precocial birds, our results suggest that there may be a trade‐off between egg‐size and fecundity, since an increase in the size of eggs within clutches may limit the time remaining within the season to lay second or replacement clutches.

A review of Gymnophalloides seoi (Digenea: Gymnophallidae) and human infections in the Republic of Korea.

Studies on Gymnophalloides seoi (Digenea: Gymnophallidae) and human infections are briefly reviewed. This minute intestinal fluke was first discovered from a Korean woman suffering from acute pancreatitis and gastrointestinal troubles. It was described as a new species by Lee, Chai and Hong in 1993. The southwestern coastal village where the patient resided was found to be a highly endemic area, and additional endemic areas have been identified. The parasite is very small, 0.33-0.50 mm long and 0.23-0.33 mm wide, and characterized by the presence of a ventral pit. The first intermediate host remains unknown, but the second intermediate host has been found to be the oyster Crassostrea gigas. Man and the Palearctic oystercatcher Haematopus ostralegus have been shown to be natural definitive hosts, and wading birds including the Kentish plover Charadrius alexandrinus are highly susceptible to experimental infection. Gerbils, hamsters, cats, and several strains of mice were also susceptible laboratory hosts. In experimentally infected mice, the parasites inhabit the small intestine, pinching and sucking the root of villi with their large oral suckers, but they did not invade beyond the mucosa in immunocompetent mice. However, they were found to invade the submucosa in immunosuppressed mice. Human G. seoi infections have been found in at least 25 localities; 23 islands on the Yellow Sea or the South Sea, and 2 western coastal villages. The highest prevalence was found in a village on Aphaedo, Shinan-gun (49% egg positive rate); other areas showed 0.8-25.3% prevalence. Infected people complained of variable degrees of gastrointestinal troubles and indigestion. The infection can be diagnosed by recovery of eggs in the feces; however, an expert is needed to identify the eggs. Praziquantel, 10 mg/kg in single dose, is effective for treatment of human infections. Eating raw oysters in endemic areas should be avoided.

Brood desertion by female shorebirds: a test of the differential parental capacity hypothesis on Kentish plovers.

The aim of this study was to examine whether the energetic costs of reproduction explain offspring desertion by female shorebirds, as is suggested by the differential parental capacity hypothesis. A prediction of the hypothesis is that, in species with biparental incubation in which females desert from brood care after hatching, the body condition of females should decline after laying to a point at which their body reserves are too low for continuing parental care. We tested this prediction on Kentish plovers (Charadrius alexandrinus) in which both sexes incubate but the females desert from brood care before the chicks fledge. We found no changes in either the body masses or body compositions of both individual male and female plovers from early incubation and throughout early chick rearing. Furthermore, the timing of brood desertion by females was not affected by their body condition. Neither did we find gender differences in the energetic costs of incubation. There were no differences in the timing of brood desertion between experimental and control females in an experiment in which we lengthened or shortened the duration of incubation by one week. These results indicate that energetic costs do not explain offspring desertion by female Kentish plovers and that the needs of chicks for parental care rather than cumulative investment by females is what determines the timing of brood desertion.

Three Nadejdolepis Spasskii & Spasskaya, 1954 (Cestoda: Hymenolepididae) parasites of Charadrii (Aves) of Belize

Three Nadejdolepis from Belize, Central America, represent new geographical records (1) Nadejdolepis paranitidulans (Golikova, 1959) (rostellar hooks 40-44 microm long) from Charadrius alexandrinus; (2) N. arenariae (Cabot, 1969) n. comb. (rostellar hooks 89 microm long) from Arenaria interpres; and (3) N. litoralis (Webster, 1947) (rostellar hooks 81-85 microm long) from Calidris fuscicollis (new host record). Additional descriptions, illustrations and information pertaining to these species are included. In addition, N. saguei Rysavy. 1967 is considered a synonym of N. litoralis (Webster, 1947). N. morenoi Rysavy, 1967 (rostral hooks 80 microm long) needs to be redescribed to confirm its validity. Two species of Nadejdolepis are transferred to the genus Microsomacanthus Lopez-Neyra, 1942 because their rostellar hooks are more diorchoid than nitiduloid, becoming M. cambrensis (Davies, 1939) comb. and M. alaskensis (Deblock & Rausch, 1967) n. comb.

Trade-off between mating opportunities and parental care: brood desertion by female Kentish plovers.

Why do some parents care for their young whereas others divorce from their mate and abandon their offspring? This decision is governed by the trade-off between the value of the current breeding event and future breeding prospects. In the precocial Kentish plover Charadrius alexandrinus females frequently, but not always, abandon their broods to be cared for by their mate, and seek new breeding partners within the same season. We have shown previously that females' remating opportunities decline with date in the season, so brood desertion should be particularly favourable for early breeding females. However, the benefits are tempered by the fact that single-parent families have lower survival expectancies than those where the female remains to help the male care for the young. We therefore tested the prediction that increasing the value of the current brood (by brood-size manipulation) should increase the duration of female care early in the season, but that in late breeders, with reduced remating opportunities, desertion and thus the duration of female care should be independent of current brood size. These predictions were fulfilled, indicating that seasonally modulated trade-offs between current brood value and remating opportunities can be important in the desertion decisions of species with flexible patterns of parental care.

BREEDING ECOLOGY AND MANAGEMENT OF SNOWY PLOVERS IN NORTH-CENTRAL OKLAHOMA

Snowy Plover (Charadrius alexandrinus) nests (n = 415) were monitored to completion on an expansive alkaline flat in north-central Oklahoma in 1995–1996. We reported Mayfield Method nesting success but relied on apparent nesting success to compare differences in successful (hatched) and lost (depredated/flooded) nests in five 1000-ha areas, by microhabitat type, and inside versus outside electric-fence predator exclosures. Apparent nesting success differed by area in 1996 and over both years. Predation differed by area only in 1995, and flooding did not differ by area. Apparent nesting success and predation differed by microhabitat type in 1995 and over both years. Differences were observed among depredated and flooded nests inside versus outside electric-fence predator exclosures. Canids and gulls were primary predators. Nests associated with habitat improvements (1995) and near driftwood debris (1996) encountered higher predation, and nests near driftwood debris were more susceptible to flooding both years. We identified an area on the alkaline flat with the highest nesting success and lowest predation where future conservation efforts for Charadriiformes could be implemented.

Trace elements accumulation in waders from Asia

Concentrations of V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Hg, Tl, and Pb were determined in the liver of 9 species of waders including migratory and resident collected from north Vietnam, south India, and the Philippines. Renal Cd concentrations were also determined. Most elements showed no significant differences between genders and among localities. Concentrations of almost all the elements in birds, except for Cr and Se in the kentish plover from Vietnam, were found to be decreased or less varied during the wintering season. Toxic element levels in waders were dependent on the migration distance. Pb levels in dunlins from Vietnam and Cd levels in pintail snipe from Philippines seemed to be in toxicologically critical on their health condition.

Habitat Use and Reproductive Success of Western Snowy Plovers at New Nesting Areas Created for California Least Terns

The Pacific coast population of western snowy plovers (Charadrius alexandrinus nivosus) was listed as threatened under the Endangered Species Act (ESA) in 1993 and its decline is primarily attributed to habitat loss. In southern California, snowy plovers typically nest in association with federally endangered California least terns (Sterna antillarum broumi). Since least terns were afforded protection under the ESA, the creation of nesting habitat from dredged materials has been a popular component of habitat restoration to partially compensate for wetland loss in this region. We had a unique opportunity to monitor habitat use and reproductive success at newly created habitats associated with the restoration of Batiquitos Lagoon, San Diego County, California from 1994 to 1998. We also compared hatch and fledge rates and habitat characteristics of snowy plovers nesting at new nesting areas at Baliquitos Lagoon to a nearby natural beach and a dredged-material area created in the 1970s. The number of nesting attempts by snowy plovers increased from 5 in 1994 to a high of 38 in 1997, and plovers nested on 4 of the 5 created areas. Fledge rates at Batiquitos Lagoon varied annually and declined after the initial colomzation in 1995. Fledge rate in 1995 was higher at the newly created area than at the older dredged-material and natural beach areas in any other year. Nests on the created areas at Batiquitos Lagoon were surrounded by less vegetative cover, less debris, and shorter vegetation than nests at the older dredged-material and natural beach areas. Nonbreeding snowy plovers used created habitats within the lagoon, and more plovers used the lagoon and its adjacent beach during fall than winter. Predation pressure and habitat quality were important factors determining use and reproductive success on created areas at Batiquitos Lagoon.

Replacement Clutches by Kentish Plovers

We examined factors affecting renesting rates in a population of Kentish Plovers (Charadrius alexandrinus) in southern Spain over six breeding seasons. We show that renesting was mainly constrained by time, and not by female body condition. Renesting partially compensated for initial clutch losses. The interval from loss of the first clutch to initiation of the replacement clutch was not affected by the number of days of incubation preceding nest loss. Renesting plovers moved considerable distances from first nests. Distances moved between nesting attempts by pairs that had lost chicks were similar to those of pairs that lost eggs. Nest cover did not differ between first and second nests when the first nest was successful, but it was greater in second nests when the first nest was unsuccessful. Yet, nest cover had no influence on the fate of such replacement clutches, probably due to a high diversity of predators at our study site. Females that laid replacement clutches did not delay breeding or breed less frequently in years after they had laid replacement clutches. Even when the success of replacement clutches is moderate, this breeding strategy may be important in accounting for individual lifetime productivity, especially when nest predation is high, as in the studied population.

Brood desertion and polygamous breeding in the Kentish Plover Charadrius alexandrinus

In the Kentish Plover Charadrius alexandrinus one of the adults, typically the female, deserts the brood when the chicks are a few days old. Once parental care is terminated, adults may initiate a second nesting attempt if sufficient time remains within the season. For these nests, individuals pair with different mates from those of the first nesting attempt, thus becoming sequentially polygamous. In a small population of Kentish Plovers in Fuente de Piedra lake (southern Spain), the duration of biparental care of broods was longer than in other localities. It also showed considerable variation between years that was evidently related to Gull‐billed Tern Gelochelidon nilotica predation pressure on the chicks. There was year‐to‐year variation in the number of polygamous matings. Both the duration of the breeding season and nesting success in the first half of the season limited the occurrence of polygamy. Despite females deserting broods earlier than males, the interval between the first and second nesting of polyandrous females and polygynous males was similar. The interval was not affected by the body condition of females after the first nesting attempt, nor by problems related to egg formation ability, but was probably due to the availability of potential mates. More females than males initiated second nests, suggesting that polygamous opportunities were more limited for males than for females. In terms of delayed breeding, reduced survivorship or reduced breeding opportunities in years following polygamous breeding, polygamous individuals did not have greater costs than non‐polygamous ones. Females with second nests did not seem to be selective in mate choice, mating with any available male. Mates for second nests may therefore be of lower quality than those for first nests, as judged by male plumage characteristics. Clutch sizes and egg characteristics of polyandrous females were similar in first and second nests. Nest success of second nests was only 40% of that of first ones, with nest desertion accounting for 60% of the losses. As the costs of polygamy are apparently low and as breeding success is very variable among years, polygamous breeding of the long‐lived Kentish Plover may be an important breeding strategy with which to increase individual lifetime reproductive success.

Parental behaviour in Kentish plovers: who cares?

Parental behaviour in Kentish plovers: who cares?

Brood desertion in Kentish plover: sex differences in remating opportunities

To understand the evolution of parental care, one needs to estimate the payoffs from providing care for the offspring and the payoffs from terminating care and deserting them. These payoffs are rarely known. In this study we experimentally estimated the rewards from brood desertion in a species that has a variable pattern of parental care. In particular, either the female or the male parent may desert the brood in Kentish plover Charadrius alexandrinus, so some broods are attended by one parent of either sex, whereas in other broods both parents stay with the brood until the chicks fledge. We created single males and single females by experimentally removing the other parent and the clutch. The expected remating time of males was significantly higher (median: 25.4 days) than that of the females (5.3 days, p , .0001). The expected remating time tended to increase over the breeding season in both sexes, although the increase was significant only in females. The new nest of remated males was closer to their previous territory (mean 6 SE, 46 6 8 m) than that of the remated females (289 6 57 m, p , .001). Hatching success of new nests was not different between remated males and females. Our results demonstrate that the remating opportunities are different for male and female Kentish plovers and these opportunities vary over the season. We propose that the remating opportunities were influenced by the male-biased adult sex ratio and the seasonal decrease in the number of breeders. However, we stress that measuring remating times is a more direct measure of mating opportunities than calculating the operational sex ratio.

Brood desertion in Kentish plover: the value of parental care

To understand the evolution of parental care, one needs to estimate the payoffs from providing care for the offspring and from terminating care and deserting them. In this study we estimated the payoff from care provision, and in a companion paper we analyze the payoff from offspring desertion. In the current study we experimentally investigated the influence of the number and sex of attending parents on growth and survival of offspring in the Kentish plover Charadrius alexandrinus, in two sites (A and B). Either the male or the female parent was removed from some broods at hatching of the chicks (female-only and maleonly broods, respectively), whereas in control broods both parents were allowed to attend their young. At site A survival of the chicks was lower in uniparental (male-only and female-only) broods than in control broods, whereas we found no difference in brood survival at site B. Brood survival decreased over the season. Removal of either parent did not influence the growth of the young, although growth varied over the breeding season, and it was significantly different between the sites. These results suggest that the payoff from parental care decreases over the breeding season and that the value of parental care (i.e., the contribution of parents to the survival of their young) may depend on the environment. Key words: biparental care, Charadrius alexandrinus, Kentish plover, mate removal, offspring desertion, parental care, uniparental care. [Behav Ecol 10:191‐197 (1999)]

Conservation and management-oriented ecological research in the coastal zone of Baja California, Mexico

This paper presents the main results of two studies of contrasting natural and man-induced conditions along the Pacific coast of Baja California (Mexico), based on the assumption that ecological insight can be obtained from man-induced modifications insofar as relevant activities are explicitly addressed as parts of the systems under study. The study is concerned with a fragmented coastal succulent-sage scrub and showed that several patches of different size and age may harbor as many species as non-fragmented areas, and that 83% of the original species assemblage persisted in the fragments, in which the invasion by opportunistic exotic species may not progress beyond certain limits. The study of dune-backed and urban-backed beaches showed a significantly greater abundance of the Snowy Plover (Charadrius alexandrinus) at the dune-backed beach, where a much more active back-shore feeding of adult birds and the only evidences of breeding occurred. Both studies refer to landscape features of regional concern and its results may be used in conservation management. The results on fragmented coastal succulentsage scrub may encourage alternative urban designs that keep patches of the original landscape, thus meeting existing requirements of low density urban development for most of the coastal succulent-sage scrub area. The evidence presented on the negative effects of dune destruction on the abundance, feeding and reproductive performance of a threatened bird species has a bearing on the topic of biodiversity management. It may also contribute to the conservation of the coastal dunes system.