Thursday, 25 July 2013

Terns Feel The Heat

Trust the Irish to spend all year wishing for sunshine & warmth but when it does finally come it suddenly gets "too hot"!

At least for the terns they have a genuine excuse. The heat generated off a shingle beach on a sunny day is quite a few degrees higher at ground level than what we experience several feet up. This is partially the reason why terns, as well as plovers & Oystercatchers, choose to nest on shingle & sandy beaches. Not only are their eggs & chicks well camouflaged against it, but those extra few degrees can make all the difference when it comes to keeping them alive.

But saying that!... Over the past two weeks it was often quite apparent that even the terns & plovers were starting to reach their limits. A scan along the beach on a hazy afternoon often revealed chicks & adults lounging around on the shingle with their eyes squint & beaks open, trying to keep cool (thermo-regulating). Some chicks could also be found trying to make the most of whatever shade was available, huddled against lumps of seaweed or driftwood washed up on the shoreline.

A warm chick poking it's head out from underneath it's equally warm parent! © Andrew Power
A rather uncomfortable looking fledgling © Niall Keogh
Prior to the chicks hatching, we provided the terns with a simple, yet effective source of relief from the elements. A total of 30 'chick shelters' were deployed along the beach in areas where we felt would be of most use, often a few meters on the seaward side of each nest. The shelters themselves are concrete roof ridge tiles, about 2 foot long. The grey colour of the shelters blends in perfectly with the shingle & they are sufficiently long enough to stop a chick being dragged out by a Sparrowhawk or Kestrel. In previous years they have been occupied by chicks during spells of heavy rain but this year we are recording good uptake but for completely the opposite reason! Both large fledglings & smaller 'fluffy' chicks can regularly be seen whiling away the hottest parts of the day under the shelters, waiting patiently for the parents to arrive back with a juicy, fluid filled fish.

A small tern chick taking refuge from the baking midday sun © Andrew Power
A nearly fledged tern, cooling down © Niall Keogh
Even some of the young Ringed Plovers have been seen hanging around the shelters © Niall Keogh

In years gone by, hot summers have led to some chicks dying due to over-exposure but thankfully this year we haven't recorded any losses as such. Chick shelters doing their job so! 

Anyways, back to rain...

No comments:

Post a Comment