Chlidonias Hybrida Research Articles

Assessing Growth and Age of Whiskered TernChlidonias hybridaChicks using Biometrics

The growth of Whiskered Tern Chlidonias hybrida chicks was investigated in Lake Grand-Lieu, western France. Body mass, tarsus, culmen and wing lengths of 33 chicks from 19 nests held in enclosures were measured at intervals of 2–3 days during the rearing period (0–20 days). The repeatability between two observers in chick body size measurements was generally high (overall 0.94), with the highest value for the wing length. Tarsus length and body mass increased fast and reached asymptotic values at about 14 (23.23 mm ± 0.18 SE) and 16 days (92.35 g ± 1.82 SE). The body mass growth rate (K, resulting from a logistic model) was 0.294 g day-1 ± 0.016. The linear growth rate at age 3–9 days was 6.32 g day-1 ± 0.28 SE. The standardized linear growth rate was 7.0% of adult body mass, which was in the range of values recorded for the closely related Black Tern Chlidonias niger (6.5–7.9%). The culmen and wing were still growing at fledging (age 20 days), asymptotic values had clearly not been reached. Before fledgi...

Indirect evidence of conspecific nest parasitism in the colonial whiskered tern ( Chlidonias hybrida)

Conspecific nest parasitism (CNP) is widespread among birds and is particularly common in colonial species. Nevertheless, this reproductive tactic is remarkably little described in terns. In this study we use egg morphology as indirect evidence of CNP in the whiskered tern ( Chlidonias hybrida) in 17 colonies from two French populations. We study CNP with respect to the duration of egg laying (i.e. clutch size), and also present some behavioural aspects that could facilitate CNP. From the inspection of 121 two-egg, 279 three-egg and 11 more egg-clutches, we detected a minimum %CNP of 9.2% for the two study populations, combined with large differences between the two populations (4.0% vs. 14.5% in three-egg clutches) and between colonies (0 up to 30%). %CNP was significantly higher in three-egg (9.0%) than in two-egg clutches (1.7%), suggesting that duration of egg laying is a determining factor of parasitism. The rather high %CNP detected in this species might be facilitated by (1) the observed long unattendance of nest by any of the pair members, mainly during the pre-incubation period, and (2) high synchrony in laying dates within colonies. A possible link between nest density and CNP rate was suggested. Finally, we encourage new investigations of CNP in other tern species. To cite this article: J.-M. Paillisson et al., C. R. Biologies 331 (2008).

Super-normal Clutches and Female-female Pairs in Gulls and Terns Breeding in Poland

Abstract Super-normal clutches (five eggs or more) in the Caspian Gull (Larus cachinnans), Mediterranean Gull (Larus melanocephalus) and Whiskered Tern (Chlidonias hybrida) are described. These species have regularly bred in Poland since the beginning of the 1990s. The occurrence of super-normal clutches was 1.8%, 4.1% and 0.3% in the Caspian Gull, Mediterranean Gull and Whiskered Tern, respectively. The first descriptions of a female-female pair in the above species as well as in the Yellow-legged Gull (Larus michahellis) and an unusual mixed female-female pair of two gull species (Yellow-legged Gull and Caspian Gull), never mentioned in the literature before, are also presented. The first fully documented case of a multi-female association of the Mediterranean Gull was also identified. The frequency of the SNCs in this study was higher than in other colonies located in different parts of the geographical range of the species.

Reproductive parameters in relation to food supply in the whiskered tern (Chlidonias hybrida)

It is generally accepted that breeding terns are sensitive to food supply and that their reproductive effort could be substantially affected by the availability and access to resources. In this study we examined reproductive parameters in the whiskered tern Chlidonias hybrida in relation to food supply during the courtship feeding period (food brought by males to females) over a 2-year period (2004–2005). We also studied whether the condition of the nestlings [body condition index (BCI)] was related to a proxy of the reproductive investment of the adults (the clutch size) during a season of food shortage. Behavioural observations showed a decrease in the intensity of male courtship feeding between years (2004 > 2005), and a strong shift in the relative abundance of the two prey groups (invertebrates/fish; invertebrate prey dropped from 88.0 to 49.3%) brought by males. This change in food delivery rates did not result in a delay in laying, but there was a significant difference in mean clutch size between years (2.71 ± 0.49 eggs in 2004 and 2.05 ± 0.78 eggs in 2005) without any within-year variation in relation to the laying dates. The egg size (volume and length) was related to the year (2004 < 2005), suggesting a trade-off in the quantity and the quality of eggs between the two seasons. We also found no evidence that the investment in a large clutch affected nestling BCI in the course of the food shortage season. Since many pairs (about 60%) interrupted breeding during the incubation stage, we assumed that parents that succeeded in rearing nestlings in these conditions were probably ‘high-quality’ individuals. Our results therefore showed that whiskered terns are sensitive to the varying food conditions they experienced throughout the courtship period. The diversity of prey types could be a key factor in the reproductive investment of this tern species.

Distribution and abundance of grebes, pelicans, darters, cormorants, rails and terns in the Alligator Rivers Region, Northern Territory

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of Australian pelicans (Pelecanus conspicillatus), darters (Anhinga melanogaster), little pied cormorants (Phalacrocorax melanoleucos), and whiskered terns (Chlidonias hybrida) on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela plain. The aerial surveys indicated that the Magela floodplain was inhabited by few of these birds during the wet season (November-March), but that numbers then increased substantially in the dry season. The Nourlangie floodplain showed similar patterns, but the numbers of birds tended to be lower. Birds were generally uncommon on the shallower East Alligator and Cooper floodplains. Ground surveys suggested that the birds sought out the persistent swamps that characterise the Magela floodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities; on the basis of correction factors calculated from ground surveys, peak numbers on the five floodplains were roughly estimated to be about 2000 darters, 9000 little pied cormorants, 55 000 Australian pelicans and 50 000 whiskered terns. Little black cormorants (Phalacrocorax sulcirostrus) were sometimes abundant, but their sporadic occurrence prevented analysis of seasonal trends. Australasian grebes (Tachybaptus novaehollandiae), great cormorants (Phalacrocorax carbo), pied cormorants (Phalacrocorax varius), buff-banded rails (Rallus philippensis), Baillon's crakes (Porzana pusilla), white-browed crakes (Poliolimnas cinereus), purple swamphens (Porphyrio porphyrio), Eurasian coots (Fulica atra), silver gulls (Larus novaehollandiae), white-winged terns (Chlidonias leucoptera), gull-billed terns (Gelochelidon nilotica) and Caspian terns (Hydroprogne caspia) were recorded in low numbers. The Alligator Rivers region acted as an important dry season refuge because of the unusually persistent fresh waters of the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain.

THE INUNDATION ZONE OF THE NIGER AS AN ENVIRONMENT FOR PALAEARCTIC MIGRANTS

SUMMARYOf at least 350 species so far recorded within the boundaries of the Niger Inundation Zone, no less than 108 (31%) are wholly or partially of Palaearctic origin. Five main habitats are recognized in the region: wetland, hygrophilous grassland, transition zone, non‐flooded areas and aerial. The habitats, the Palaearctic migrants and their possible Ethiopian competitors are described and discussed.The annual Niger flood regime enables Palaearctic waterbirds to find suitable habitats somewhere within the region during all seasons, but most widely during the autumn and winter months of the flood recession. Non‐aquatic species inhabiting flood plain grassland are scarce during the Palaearctic autumn, when the growth of vegetation reaches its maximum, becoming commoner and more diverse during the winter months. Wetland warblers of the genera Acrocephalus and Locustella have not been recorded on autumn passage. It is suggested that in some years at least, these and other trans‐Saharan migrants from the West Palaearctic overfly the Sahelian latitudes of mid‐West Africa. Species inhabiting the transition zone (which increases in area during years of below average rains and floods) are most in evidence at the end of the winter period and during the spring hot dry season, prior to northward trans‐Saharan migration. Habitats and species encountered in the non‐flooded areas are similar to those recorded in the Sahel zone elsewhere in West Africa.Aerial habitat is utilized by Common Swifts arriving en masse in early August, at the maximum development of the south‐westerly monsoon airstream. Several aquatic species and the first few trans‐Saharan migrants also occur during the summer rainy season.Some species (e. g. Whiskered Tern, Lesser Kestrel, Turtle Dove, Short‐toed Lark and Sand Martin) are most numerous during the late winter and spring hot seasons, when conditions provided by the Inundation Zone may be more suitable for pre‐migration feeding than in other parts of the Sahel zone. As yet there is virtually no information available to determine any effects that drought seasons or flood variation may have on the migrant populations.

The family prosthogonimidae (Trematoda) in Australia

The family Prosthogonimidae (Trematoda) in Australia. International Journal for Parasitology 3: 853–862. The family Prosthogonimidae has previously been known in Australia by three species of Prosthogonimus Lühe, 1899 (from birds) and by Coelomotrema Angel, 1970 (from marsupials). Two new genera are now proposed: Cylindrotrema cygni from Cygnus atratus (Latham) (caecum), and Mawsonotrema eudyptulae from Eudyptula minor (Forster) (liver). Prosthogonimus vitellatus Nicoll, 1914 is recorded from three new hosts, Gymnorhina tibicen leuconota (Latham), Phalacrocorax melanoleucos (Vieillot) and Chlidonias hybrida (Pallas), and the species is redescribed from 11 specimens from the first of these. The life history, not known for any Australian species, is discussed. The only plump-bodied genera in the family are Coelomotrema, Cylindrotrema and Mawsonotrema, all of which are confined to Australia. Mawsonotrema differs from all other members of the family in the position of the genital pore, which is away from the anterior end of the body, lying against the anterior border of the acetabulum.

Some Nematodes from Australian Gulls and Terns

A table is given showing the incidence of helminth parasites in gulls and terns from South Australia, from which it may be seen that nematodes occur less frequently than cestodes or trematodes. The only new species recorded is Capillaria thomascameroni from Larus novaehollandiae. Other species recorded with some redescription are: Cosmocephalus jaenschi Johnston and Mawson from Chlidonias hybrida fluviatilis; Pectinospirura argentata Wehr and Streptocara pectinifera (Neumann) from Hydroprogne caspia; Seuratia shipleyi (Stossich) from Sterna fuscata and Anous stolidus; and Contracaecum magnicollare from A. stolidus and Anous minutus. Tetrameres spp. are noted from Chlidonias hybrida fluviatilis and Geochelidon nilotica macrotarsa; Eufilaria sp. from L. novaehollandiae; and Paryseria sp. from Sterna bergii cristata. Four female worms in very bad condition from G. nilotica macrotarsa appear to belong to the Habronematinae.

Natural Selection, the Costs of Reproduction, and a Refinement of Lack's Principle

Natural Selection, the Costs of Reproduction, and a Refinement of Lack's Principle