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...

Fledgling Success

Friday 12th July saw a major 'terning' point in this years project (no excuses for the terribly awesome pun).

Having had the previous day off, re-acquainting myself with the delights of the 'real world' (namely laundry duties, an overcrowded Dublin City, public transport full of screaming children etc.) I was more than eager to head back to the colony on Friday afternoon & start my weekend shift.

Once back on site, myself & Andrew were stood staring at the colony, discussing the comings & goings of the previous day during our cross-over between shifts, when all of a sudden, a strangely familiar high pitched, squeaky 'peep' call could be heard around the area of The Breaches estuary outlet. Just as expected it was being emitted from a fledgling Little Tern, flying strongly over the beach!

We spent the next few minutes savouring the moment. After watching & protecting these terns every waking minute of the day & night for the past two & a half months it was hard not to get excited by the sight of a fully fledged juvenile having the time of its life flying about the place!

And what's more... it wasn't alone! By the end of the evening we had seen three different juveniles which were fully capable of flight. Fantastic! We reckoned they were from nests K2 (2 young) & K5 (1 young) which would mean they were between 19 & 22 days old between the youngest & oldest of the lot of them.

One of our first fledgling terns © Niall Keogh

These past few weeks of unbroken sunshine & calm conditions have provided optimum feeding conditions for the terns, with chicks being fed from 5am straight through to 10pm with only a short lull during the hottest parts of the afternoon. Sprat seems to be the order of the day for the 10+ day old group of chicks, which are being delivered at a rate of 2-4 per hour per hungry mouth! 

This excellent feeding has led to the chicks developing ahead of schedule & most seemingly taking flight at the younger end of the expected fledging time scale (between 19 & 23 days). As such, dawn & dusk counts along the foreshore are providing us with up to 100% of our expected fledglings each day. Now in the order of c.40 juvenile Little Terns!!! Furthermore, the oldest group of fledglings are now really getting the hang of proper flight & can often be seen up to 100m offshore in loose flocks, practice diving for fish, picking up bits of floating debris & joining in with the occasional 'dread' of flocking adults.

Little Tern fledgling on the younger end of the scale, still with bits of downy chick fluff on its head © Niall Keogh

18 day old Little Tern...ready to take it's first proper flight in a day or two © Niall Keogh

The Breaches estuary outlet into the sea which splits the beach in two near the tern colony had taken a somewhat undesired route for most of the summer, edging slowly Northwards, creating a steep bank which was getting perilously close to the main fence as it eroded away after each high tide (we had to move the corner of the fence inwards on a number of occasions to stop it ending up in the sea!). But thankfully the outlet has been re-profiled by digger since then, changing the course to flowing straight out from underneath the railway bridge. This has left a long shingle spit leading south from the colony where the old outlet used to be and at high tide it is surrounded by water on three sides, creating a perfect 'hang out' for fledglings & waders such as Dunlin. As this area is proving so important for the older tern chicks, we have cordoned it off with rope & signs to ensure none get trampled there. Still a great spot to have a look at from the safety of the opposite bank with a telescope.

Erosion!

Newly formed shingle spit at high tide

A few late nesting attempts (it's getting on a bit now lads!) have also been discovered bringing us up to a total of 45 pairs breeding on the beach this season. Three of the these nests have 'failed' in such that the eggs didn't hatch, even up to a week beyond the latest date for expected hatching. A few nests every year go this way unfortunately but it may simply be a case of the breeding birds in question being quite old, producing infertile eggs.

So as of this evening we have 42 active pairs with 65 chicks (c.40 of which have fledged) & 10 eggs left to hatch over the coming week!

Hatch...Eat...Run...

The June Spring Tides which caused so much heartache in 2012 came & went this season without any hassle thanks to prevailing light-moderate Westerly winds. Furthermore, a good spell of dry, warm weather has ensured that the first group of chicks to hatch since Sat 22nd June have been treated to optimal conditions during their crucial first few days of life.

We've been weighing & measuring each new brood regularly as well as observing the species, size & frequency of fish brought in by the adults. Initial results are looking good with one chick in particular jumping from 7.2 grams on the day of hatching to 18.55 grams three days later! The parents of a brood of three have been kept busy & were noted bringing in as many as 12 fish (mostly small sandeels) per hour yesterday evening!

The majority of the chicks are now very mobile & have been led by their parents away from their original nest scrape, out of the main area of fencing & onto the foreshore. This is normal behaviour & a sort of tern 'creche' will form along the mean high water mark over the coming weeks where feeding can be observed throughout the day. Access to the foreshore alongside the colony is still restricted in order to avoid any unwanted trampling so if you're planning on visiting the beach at Kilcoole please follow on site instructions as laid out by the wardens.

Monitoring chick growth & development...a tough job! © Niall Keogh

Adult & chick © Niall Keogh

Rare moment seeing a tern chick just after hatching © Niall Keogh

It seems to be an odd year with regards potential predators. The 'usual suspects' such as Fox, Hedgehog, Hooded Crow & Rook have all been thin on the ground for the most part with very little corvid activity on the beach or in the estuary, just two Hedgehogs found at night along the coastal track (usually a good few more expected by now) & Cole reports just the one sighting of a Fox near the beach well to the North of the colony which legged it as soon as he saw it.

Saying that, we have experienced some losses to less familiar species, namely Oystercatcher & Sparrowhawk. A total of 3 nests with 2 eggs each were eaten by an Oystercatcher between 19th & 25th June. We have been closely observing all the Oycs in the vicinity & it would appear that the individual in question is a lone non-breeder which has been seen foraging in the tideline near the colony. Our resident breeding Oycs have taken no notice of any nesting tern nests near them all season & have proved invaluable as colony 'security', chasing away any potential avian predators that fly over the beach. In fact, they have also been chasing this lone Oyc off their territory & as such it hasn't been seen in quite a few days.

Little Tern eggshell after being poked & eaten by an Oystercatcher © Niall Keogh

A male Sparrowhawk caught an adult tern at 05:30am on 20th June after which a pile of plucked tern feathers was found along the west boundary of the flexi-net fence. The first proven case of predation by Sparrowhawk at the Kilcoole Little Tern colony since 1997! It made a further six attempts on the colony over the next five days but luckily the terns & Oycs had caught on to the Sprawk's ambush tactics and promptly saw him off with great enthusiasm. The same can be said for the wardens who chased after it also!

Remains of an adult Little Tern after being caught & plucked by a male Sparrowhawk © Niall Keogh

But aside from these unusual predation events, we're happy to report everything else is going well. Eggs are hatching on time, chicks are getting stuffed with fish, disturbance has been kept to a minimum & the support from the local public seems to be ever growing (lots of folk enjoying nice views of chicks lately!).

So as of this afternoon the scores on the shores are as follows: 37 active pairs with 36 chicks & 34 eggs left to hatch.

Not sure if anyone has told this chick that it will be another 3 weeks or more before it will fly. Hasn't stopped it from exercising its wings all the same! © Niall Keogh

New Recruit!

Just a quick post to say our first chick of the year hatched today! 

K2 was the first nest which we expected to hatch and it didn't disappoint. The second egg in the nest had a well defined hole in the shell, poked from the inside out so hopefully today's chick will have a sibling by tomorrow. A couple of other nests are showing early signs of hatching too. Then a large batch of nests are due to hatch from mid-week onwards so it will be all go for the wardens.

We're currently in the midst of a run of high Spring Tides but thankfully the winds are from the West for the next few days so fingers crossed we will get through them with no trouble.

K2 chick & hatching egg © Niall Keogh

Plumbers, Snatchers & Grass Raptors

The section of beach & sand dune at the tern colony site which is fenced off & wardened during the breeding season is also home to a number of other species which we monitor & protect, namely Ringed Plover, Oystercatcher & Skylark.

Ringed Plovers tend to nest a couple of weeks earlier than the terns and there are often pairs already on eggs when we arrive in early May. This year however it was well into mid-May by the time we found the first clutch, seemingly in accordance with the late Spring all round. Since then all has been going well for them and we have a total of 7 breeding pairs which is about average. Two pairs are still incubating eggs whilst the remaining five pairs have hatched their chicks, which can be seen running along the short vegetation line between the shingle beach & sand dunes where they feed on tiny invertebrates.

Ringed Plover incubating, hatching & chicks © Niall Keogh

Our usual two pairs of Oystercatchers laid three eggs each. One clutch hatched on Monday with the young being diligently cared for by their raucous parents ever since then (I get mobbed by the adults constantly, even whilst on the path away from the beach!). The second pair have just hatched their eggs between yesterday evening & this morning! Unlike the Ringed Plover chicks which feed themselves on insects, the parent Oystercatchers must collect food for their young in The Breaches estuary & fly it across to the beach where the chicks are located. A lot of effort when carrying one ragworm at a time!

Oystercatcher pair, clutch of 3 eggs & newly hatched (and hatching!) chick © Niall Keogh

Finally, we have one pair of Skylarks nesting amongst the Marram grass inside the colony fence. They successfully raised one brood of 2-3 young already and appear to be making a start on a second (the pair was seen mating & carrying nesting material). The male continues to sing his heart out, way up overhead during song flight, but also from the ground & on the flexi-net fence around the tern colony.

Singing Skylark © Paul Smith

And if you we're wondering what the title of this blog post is about... We've been making up nick-names for most of the bird species around Kilcoole! So guess which is which!

Mid-June Update

The previous tern blog post mentioned that after a late start, the first egg was found on 27th May. It took a few more days for momentum to pick up but from the 5th June onwards the colony seemed to get into the swing of things and multiple new nests were found each day for the next week or so with 60-80 birds present on most days.

Little Tern egg with an unusual pattern  © Niall Keogh

Amongst this flurry of new nesting we also encountered a small number of losses. Four nests (K1, K3, K8 & K20) abandoned within a few days of laying their first eggs. Reasons for this remain unclear but in previous years we have attributed predation of adult terns by Peregrines & long spells of rough/wet weather as potential causes of nest abandonment. Another theory is that some pairs may involve first time breeders, which might not have the hang of what they are meant to be doing! Nest K23 decided to lay its eggs way out beyond the fencing, far too close to the shoreline and before long it was washed away by a high tide with a backing wind. Again, most likely an inexperienced pair which will hopefully lay a replacement clutch this week further up the beach. Another nest which was lost (K7), had 1 egg predated by an as of yet unknown small mammal. Small shards of egg shell & spilled yolk were all that was left in the nest scrape, which on previous years experience would tie in with those signs known to be left after Hedgehogs had made it into the colony. We performed a thorough check of the sand dunes in the immediate area but found no signs of tracks or droppings. All the tern, Ringed Plover & Oystercatcher nests surrounding K7 have remained active since with no egg loss so we are hopeful that this was an isolated event.

 

An incubating Little Tern...safe & sound! © Niall Keogh

So after losses have been taken into account, the total number of active pairs as of this evening stands at 28 nests with 57 eggs. This is certainly much lower than what has come to be expected for this stage of the season over the past decade when 50+ pairs could be established. We think this is due to a combination of the late Spring/breeding season being experienced by many species this year and also as a result of the high tides & storms which led to no successful breeding in 2012. Perhaps many of the regular Kilcoole breeders have opted to try somewhere else this year?

Switching colony sites in response to factors such as vulnerability to tides, increased disturbance by people or the presence of certain predators is normal behaviour for terns. Little Terns in particular are known to move location within the same season if the initial area they chose doesn't suit. At the same time they are also known to return the next year if all seems ok. As such we aren't too worried by the fact that there are (relatively) low numbers of breeding birds present this year. In fact, we're delighted there's some back at all!

With that in mind, we'll be doing our utmost to ensure that those birds which have graced us with their presence this year will be pampered, guarded 24/7 & treated to the full VIP wardening package!

A joint BirdWatch Ireland Wicklow & Carlow Branch outing to the colony site today was well attended! © Andrew Power

A 'blue' variety of Little Tern eggs © Niall Keogh

Guided Walk this Sunday

The annual outing to Kilcoole led jointly by the BirdWatch Ireland Wicklow & Carlow Branches will be held this Sunday, 16th June meeting at Kilcoole train station car park at 10:00am.

The walk will take in the birds & wildlife of the coastal marshes & seashore, culminating with a visit to the Little Tern colony where wardens will be on hand to show participants nesting terns, Ringed Povers & Oystercatchers through telescopes.

This is a free event & all are welcome!

Little Tern © Niall Keogh