Black-headed Gull (Larus ridibundus) Science Article 1 abstract In long-lived colonial birds, age at recruitment is an important life-history character. Variation in this parameter may reflect differences in several factors, including competitive ability and breeding strategies. Further, these differences may be due to timing of hatching (for instance through differences in competitive ability). We investigated […]

Black-headed Gull (Larus ridibundus) Science Article 2 abstract During early development male offspring in avian species often suffer from enhanced mortality compared to female offspring. This has been attributed to different nutritional requirements, as sex-biased mortality has been reported particularly in sexually size-dimorphic species. However, other traits of the male phenotype, such as the embryonic […]

Black-legged Kittiwake (Rissa tridactyla) Science Article 7 abstract We used doubly labelled water to study the field metabolic rates of breeding Kittiwakes Rissa tridactyla during the incubation phase, and to compare these with the metabolic rates of Kittiwakes rearing chicks. During the incubation phase, birds with two eggs spent an average (

Black Skimmer (Rynchops niger) Science Article 3 abstract During the last two decades, Black Skimmers (Rynchops niger) have become increasingly common along the southern California coast.They are now found year-round in southwestern California (Collinse t al. in press) and in northwestern Baja California (Palacios and Alfaro 1992). Little detailed information has been published, however, about […]

Black Skimmer (Rynchops niger) Science Article 4 abstract Post-natal development was studied in 40 southern California Black Skimmer (Rynchops niger) chicks in order to develop a reliable method of aging and sexing pre-flying young in this sexually dimorphic species. Ages of chicks were determined from hatching dates and were calculated also from wing chord measurements. […]

Black Tern (Chlidonias niger) Science Article 1 abstract The black tern (Chlidonias niger surinamensis) still occupies most of its former range. The continental population likely numbers in the low to mid hundreds of thousands and appears stable within the habitat that remains. However, given the severity of previous declines, conservation of the black tern still […]

Black Skimmer (Rynchops niger) Science Article 1 abstract I examined colony-site tenacity and reproductive success in 19 colonies of Black Skimmers (Rynchops niger)f or 5 yr in New Jersey . Frequent colony-site shifts occurred, and only two sites were occupied in all 5 yr. Although in one year fledging success was nearly zero due to […]

Black Skimmer (Rynchops niger) Science Article 2 abstract We compared the diurnal and nocturnal visual function in two tactile foragingwaterbird species, the red subspecies of the American White Ibis (Eudocimus ruberruber, formerly the Scarlet Ibis), which is known to feed exclusively during daytime, andthe Black Skimmer (Rynchops niger), which forages primarily during darkness. Live birdswere […]

Black Skimmer (Rynchops niger) Science Article 5 abstract Nests of Black Skimmers (Rynchops niger) (n = 37), Large-billed Terns (Phaetusa simplex) (n = 121), and Yellow-billed Terns (Sterna superciliaris) (n = 16) on an exposed sandbar in the Trombetas River, Brazil, were monitored during incubation and hatching in 1982. The species were interspersed throughout the […]

Audouins Gull (Ichthyaetus audouinii) Science Article 2 abstract During the Audouin’s Gull’s breeding season at the Ebro Delta in 1993, 24 fresh eggsfrom eight three-egg clutches (modal clutch-size) were collected at the peak of thelaying period. Eggs were processed to obtain formalin-fixed yolks, which were halvedand stained using the potassium dichromate method. Xavier Ruiz et […]