Search

Common Tern (Sterna hirundo) chicks are highly mobile, as they are semi-precocial. However, they generally stay in the territories near their nests until soon after fledging. In the salt marsh-breeding population in Barnegat Bay, New Jersey, USA, Common Tern chicks were recorded far from their nests before fledging. Movements from the nest were quantified at two islands in Barnegat Bay. For the first 1-3 days, chicks stayed very close to the nest. By 4 to 6 days of age, no chicks were within the nest cup, but they typically remained nearby, at a median distance of 0.45 m from the nest. From 1 to 3 weeks of age, median distance from the nest steadily increased from about 1 to 4 m. Among those chicks older than 3 weeks, the median distance away from the nest was 6.45 m, and none were found closer than 1.75 m. Common Tern chicks older than one week were usually not present in their territories, despite continuing to rely on their parents for care. The contrast between this and previous studies of the Common Tern may relate to habitat differences. [ABSTRACT FROM AUTHOR]

The population of Common Terns (Sterna hirundo) in Bamegat Bay, New Jersey, USA, has recently experienced poor productivity with complete or near-complete breeding failure at multiple colonies, and the number of breeding pairs has declined. Adult Common Terns were captured and banded at Pettit Island from 2010 through 2014 and at four additional islands from 2011 through 2014. Although the number of breeding pairs on Pettit Island decreased and reproductive success was generally poor, this colony was more productive than the other colonies. Data from the other colonies were too sparse to treat each site separately, and the analysis is instead based on two "locadons": Pettit Island and all other sites. Apparent survival and movement probabilities were estimated using multistate capture-recapture modeling based on recaptures combined with resighting of color-banded Common Terns. The two best supported models included location, transience, and presence or absence of color bands as variables and produced very similar parameter estimates. Adult survival at Pettit Island was estimated at approximately 0.88, which is within the range of previous estimates for Common Terns. Survival estimates for the other sites had high uncertainty but appeared to be very low, at approximately 0.71. There was no evidence that apparent survival changed across time (2010-2012 compared to 2012-2014). Movement probabilities suggest a frequency of breeding dispersal within Barnegat Bay above 6%. Detection probabilities were much higher for color-marked birds than for those with metal bands only. Low apparent survival and decreases in the number of adults probably reflect permanent emigration out of the study area. The most likely cause of this decline in the Barnegat Bay population is frequent flooding due to sea level rise and severe storms. [ABSTRACT FROM AUTHOR]

Feather sampling is often assumed to be harmless, but this assumption has not been tested. From 2008-2012, we recorded the behavior of 340 Common Tern (Sterna hirundo) chicks following the removal of a pinch of body feathers. Only 11.2% of these chicks ran after sampling and 69.4% showed no visible reaction to sampling. The probability of a chick running away increased with age. We therefore recommend that sampling be conducted as soon as possible after juvenal feathers emerge. There was evidence for individual differences in behavior: approximately 71% of chicks that ran after feather sampling also ran away when re-encountered on later dates, while other chicks rarely did so. We found no evidence that removal of feather samples increased chick mortality, supporting the assumption that this technique is minimally invasive, but small differences in mortality rates would have been difficult to detect. [ABSTRACT FROM AUTHOR]