Project Summary 2019

The first Little Tern nest was found on the 17^th May. The ‘active nest count’ peaked on 27^th May with a total of 130 nests, shortly afterwards the number began to decline due to initially undetermined nocturnal predation. Various predators were active around the colony over the course of the season, including; American Mink, Hedgehog, Rook, Red Fox and Peregrine. A total of 68 nests (52% of the colony maximum) were depredated between 27^th May – 5^th June, during which time two Hedgehogs were observed on the main colony (using thermal imaging optics) and removed. It was concluded that they were responsible for the greatest number of losses during this time having gained access to the colony by entering under the netting along the seaward side in the aftermath of tidal damage. Of the total nest losses during this period, 13 were on the satellite colony south of the breaches, of which, the greatest deficit was incurred by an unidentified nocturnal predator. The confirmed presence of American Mink in the estuary and lagoons throughout the duration of the project meant that predation by this species could not be ruled out. Additionally, sustained opportunistic predation by Rooks caused losses of individual eggs, and high levels of nest abandonments.  

During the intervening period to the 12^th June the ‘active nest count’ again rose steadily to a total of 95. However, over the course of the following days the colony sustained losses due to tidal inundation. The marine influence abated on the 15^th but not before destroying or causing abandonment of a further 33 nests (35% reduction). In the aftermath, the ‘active nest count’ rose to 80 by the 17^th June, at which point the first batch of nests were marked ‘departed’ indicating in each case that the clutch had successfully walked off the scrape. 21 nests were observed ‘departed’ between 17^th – 21st June.

Figure 1. Complete season - active nest trend (Data: BirdWatch Ireland)

From 22^nd – 31^st June, the ‘active nest count’ rose, initially quite rapidly, to 106 on the 23^rd . Subsequently the trend exhibits a brief plateau before continuing to rise steadily to a peak of 111 on the 31^st  June. (see Figure 1. for complete season - active nest trend). Based on colonial observations at this time, it is suggested that the incumbency of this latest cohort may be a proportional representation; of relaying birds faithful to the Kilcoole site and; a contingent from a neighbouring colony at Portrane, Co. Dublin (tentative). According to reports, circa 30 pairs of Little Terns abandoned breeding grounds at Portrane around this time, due to high levels of disturbance by a Fox.

From the 1st June the number of chicks departing their nests grew continuously, reducing the active nest count, eventually to zero.

A total of 269 chicks were recorded at Kilcoole in 2019 of which 253 were ringed (compared to 257 and 258 in the previous years consecutively). We are confident that ~90% of the total number fledged successfully, with the first fledgling observed taking to the wing on the 28th June. Losses to young birds were attributed to; natural causes (5), unidentified cause (4), lost at sea (1), Peregrine (4), Fox (11). Predation by Peregrine and Fox was especially pronounced towards the end of the season, with the peregrine taking fledglings on the wing and the fox stalking them on the ground by night.

A new nest was discovered as late as the 30th July containing a brood of 2 freshly hatched chicks. It was monitored apprehensively for 3 days until, alas, on the 3rd of August the chicks were gone.

Juvenile female Peregrine which frequented the colony in July taking at least 4 fledglings. (Photo: Daniele Gioppo) 

During the last few days of wardening duty on the colony some notable sightings were made on or near the site, including; comma butterfly, Green Sandpiper, and Great Egret which rounded proceedings off nicely. 

Left: Comma butterfly. Right: Great Egret and Grey Heron

 From everyone involved in the Kilcoole Little Tern Conservation Project 2019, we would like to say a big thank you to everyone who has supported the project this year.

The 2019 Team. L-R: Isabelle, Kevin, Daniele, Eilis,Chris, Alex, Steve, Darren.