Over the past 3 weeks we have been closely monitoring the behavior of the Little Terns at the colony at Baltray. From the 10th – 19th of July a small group of Little Terns (from 4 to 15 individuals) were displaying, showing signs that they might consider a late nesting attempt. Some examples of typical courtship were observed including aerial displays, where the male (calling and sometimes carrying a fish) is chased by a female, high above the colony, and then descends, gliding with his wings held in a V. On occasions we also observed a male attempting to present food as a gift to a female (see more details of Little Tern courtship here). However, despite the best efforts of the males, no evidence of nesting attempts was observed during this period.
During this time, we also focused on getting accurate counts of the numbers of Little Terns (and other tern species) roosting at Baltray. As mentioned in an earlier post, there are two areas close to the nesting colony that Little Terns use at high tide to rest, wash and preen (essential for keeping feathers healthy and free from parasites). Roost counts were carried out in the 2nd and 3rd week of July within 2 hours of high tide, when the terns naturally group together at preferred roosting areas. On average higher numbers of Little Terns were roosting earlier in the month (average of 44 birds in 2nd week of July, compared with 31 birds in 3rd week of July). A peak of 57 Little Terns (including 2 juveniles) was reported on the 12th of July. The proportion of juveniles in the roosting flocks increased as the month progressed. Juveniles made up ca. 6% of the flock in week 2 which increased to 25% in week 3. This increase is to be expected as the number of fledged juveniles from nearby colonies (e.g. including Kilcoole) increases, these juveniles together with their parents join other adults birds (both non-breeders and failed breeders) in post-breeding flocks before migration. You can follow the progress of Little Tern colonies around the Irish Sea using the following links – Kilcoole (Wicklow), Gronant (north Wales), North Wales Little Tern Group and Isle of Man (Ayres) managed by the Manx Wildlife Trust.
When the Little Terns have gathered to rest, and the conditions are suitable (wind, rain, sunshine and substrate the terns are standing on!) an opportunity may present itself to look for (and if you are persistent) and read any colour rings present. So far, all colour-ringed Little Terns seen at Baltray have come from Kilcoole. The colour-rings used at Kilcoole are dark green with 3 white letters or numbers. However it is possible that birds from Wales with yellow colour rings may turn up. A map has been created to give an overview of the colour rings observed at Baltray – illustrating where the birds were ringed. If you do observe a colour-ringed tern, you can report details to BirdWatch Ireland via this page.
This week work began to take down the fence which surrounds the colony and the site will be prepared for the winter. Remember if you are visiting the site, please walk on established paths and keep dogs on a lead. The breeding season continues into August for a number of ground nesting birds, including Meadow Pipit and Skylark and as you can see from the photos below, these species are very vulnerable to depredation from ground predators, which sadly includes dogs (and their owners).