Friday, 15 July 2011

All the terns...99!

Well it's getting to that time of the year again. The first batch of early nesting pairs & their young have already left the colony, taking the first step on their journey back to Africa for the winter!


This has become evident over the past couple of weeks as fledgling counts (which we conduct along the foreshore in early morning or late evening) have been going up & down, corresponding with similar fluctuations in the numbers of adult birds on site. This morning for instance, it was notable that the majority of fledglings along the foreshore are those at the young end of the scale (20+ days old) & can be identified by having blunt wings, sandy coloured upperparts & remnants of downy chick fluff on their head. The proportion of 'fully' juvenile Little Terns (30+ days old) with long wings, dark caps, dark bills and scaly black & grey upperparts, has decreased quite a bit. So I reckon somewhere in the region of c.45 juveniles & c.80 adults have now left the colony!


Juvenile Little Tern getting fed © Jamie Durrant
At the complete opposite end of the scale however, we're still finding new nests & yesterday I marked out our latest one (K120) which contained a single egg! As I suggested before, these are more than likely arrivals from another colony altogether which abandoned for whatever reason & moved to Kilcoole to try again. It's getting a bit silly now though as any nests that hatch out after the weekend won't be fledged by the time we finish up here for the season! 


One of the latest nests, with an interesting egg pattern © Niall Keogh
It would seem a bit harsh but I suspect & hope that many of these later nests will abandon over the coming weeks. This would actually be better off for the birds as they will be putting a lot of strain on themselves by raising chicks right up until the point when they will have to begin their return migration which could lead to the parents not being in as good condition to do so as they should be. Any late fledglings will also be at a disadvantage as they will not have had as much time to strengthen & learn to fend for themselves as the first lot have, again putting them at a disadvantage when migrating. Anyway, we'll see how the nest situation pans out over the next 3 weeks but my prediction is a run of abandonment to come.


A well grown chick on the foreshore doing it's best to hide from me! © Niall Keogh
The local predators & tides have been behaving themselves lately and we've had no recent chick losses to report. Three long dead chicks have been found however in the tideline & were most likely killed during the storm on 17th June. I have yet to find anymore on subsequent searches so it seems that we got away lightly (relatively speaking)! Since corvid attacks have stopped, egg loss has centred mostly around infertility & abandonment. A total of 7 nests have been abandoned this season (due to various reasons such as bad weather & Peregrine predation of adults). Furthermore, the entire clutch from 5 nests have failed to hatch along with single eggs from a couple of nests containing 2 or 3 eggs. This is just par for the course with some pairs, perhaps involving very young or very old pairs.

So the figures at present are: 130 nesting attempts have been made by 99 pairs with 132 young (c.88 fledglings & c.44 chicks) so far & a further 36 eggs left to hatch from a total of 21 nests.

Eggs which fail to hatch often contain dead chicks like this one © Niall Keogh
Hedgehog looking rather guilty after being caught by Cole trying to sneak in! © Niall Keogh



2 comments:

  1. Well done everyone....doing a great job.

    Any news on the Shelduck nest?

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  2. Hi Yvonne,

    Just saw the female Shelduck today with 5 small young in the channel near where you found the nest!

    Niall

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