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Saturday, 25 June 2016

Magharees tern numbers tumble

What's happened to the terns on the Magharee islands? A visit there on 7th June showed that numbers of nesting terns on several of the islands have plummeted. On Illauntannig in particular, where normally up to 50 or so pairs of Arctic Tern nest, only 7-8 pairs were present. 

Tern nesting area (foreground) on Illauntannig, a previous Arctic Tern and Little Tern colony, now with only two pairs of Little Tern.

Arctic Tern, Illaunturlough, 7th June 2016 (all photos: Michael O'Clery).

Arctic Tern, Illauntannig, 7th June 2016.

In recent years Common Terns had increased, from two pairs on Illauntannig in 2003 to a peak of 38 in 2007. In June 2016 only two non-breeding birds were seen.

Common Tern, Illauntannig, 7th June 2016 (all photos: Michael O'Clery).

Perhaps most seriously of all, there were only two, possibly three, pairs of nesting Little Terns on Illauntannig. The lowest previous count at this site - the only breeding site on the entire SW coast of Ireland - was of 18 pairs in 2007. In most summers in the past ten years, 20 to 30 pairs have been the norm.

Little Tern, Illauntannig, 7th June 2016.

By way of something of a caveat, only four of the main islands were checked, and it is possible that the Arctic and Common terns have relocated to other island, e.g., Illaunammil, and the remote Illaunnabarna, both of which have held important numbers in the past. For Little Terns however, the only island with suitable shingle beach nesting habitat is on Illauntannig, so it is most unlikely to be nesting undetected elsewhere on the island group.

There are also natural fluctuations at most tern nesting sites around Ireland and, as not all islands were visited this June, it is hard to draw definitive conclusions about this years apparent decline, but for Illantannig, these are the lowest counts of nesting tern numbers ever.

Rock Dove, Illauntannig, 7th June 2016.

Common Gull numbers are down on Illauntannig too, with only about 30 pairs nesting at one colony on the island, when in previous years up to around 80 at two to three colonies has been the norm. None were nesting this summer on Doonagaun, Illaunboe or Illaunanoon where 3, 11 and 35-40 pairs respectively nested in 2007.

Common Gulls, Illauntannig, 7th June 2016.

There have been no formal surveys done of the Magharees island group since the last full survey in 2006 and 2007 (see the Dingle Peninsula Bird Report, 2005–2007), but with a national seabird survey ongoing in 2016 and 2017 the visit on 7th June shows that a full survey of the island group in summer 2017 must be a priority. 

The weather has been particularly benign this spring and early summer and landings on the islands have been relatively easy for boaters, kayakers, jet skiers and the like. There have been issues on Illauntannig before about human disturbance to the bird colonies, and it is possible that pressure from the growing number of visitors is affecting the success of vulnerable ground-nesting birds.

Friday, 24 June 2016

Curlew Sandpiper at Blennerville

Adult Curlew Sandpiper, with Knot, Blennerville, 24th June 2016 (David O'Connor).

The first 'autumn' migrant of the year in Kerry.

Thursday, 23 June 2016

New record for oldest Barn Owl

Following the post HERE on Ireland's oldest Barn Owl from summer 2015, the longevity record has been broken once more by another Kerry bird.

Ireland's oldest wild Barn Owl, near Tralee, Co. Kerry, 20th June 2016 (Photo: M.O'Clery, Under licence from NPWS).

This ringed male took up residence at a nest box near Tralee, after the previous veteran male was killed on the Tralee Bypass (see this post HERE), and it was finally possible to read the ring number a few days ago.

He turns out to have been ringed as a chick at a site in east Kerry, about 20 km away, in summer 2008. At eight years of age, this is now the longest-lived wild Barn Owl so far recorded in Ireland.

Wednesday, 15 June 2016

Puffin Island

Puffin Island is a BirdWatch Ireland reserve, just 250m off the Iveragh Peninsula and is about 1.5 km long and 0.7 km wide. The only inhabitants are the tens of thousands of seabirds which make their home on the steep slopes and cliffs.

Puffin Island, from the summit, looking SW toward the Skelligs. The slopes on this western side hold most of the 5,000–10,000 Atlantic Puffin burrows (All photos: M.O'Clery, June 2016. Click the images for a closer view).

The north end of Puffin Island has more gentle slopes, with hundreds of Manx Shearwater burrows occupying the areas with the white Sea Campion flowers.

Precise numbers of seabirds present here are not accurately known, but the best recent estimate is of 5,000–10,000 pairs of Atlantic Puffin nesting each year, although the island should perhaps be named as 'Manx Shearwater Island', with some 20,000 pairs now estimated for this nocturnal species. The shearwater colony was considered to be the second largest in Ireland after Inishtooskert, in the Blaskets group, after a major survey in 2001, but the current estimate shows the size of the colony had been hugely underestimated. There is an ongoing national seabird survey which might soon reveal more about the true numbers on each of these islands.

Interestingly, the two species - Puffin and Manx Shearwater - often directly compete for burrows, and though Puffins win out on some islands, each can usurp the other, depending on the location and geography of the island. Certainly, on Puffin Island, the steeper, rockier slopes were the main areas for Puffin, while less vegetated, gentler slopes and summits were occupied by the Manx. There could be an interesting study to be done on the clashes and fluctuating fortunes of the two species along the borders between the colonies.

Atlantic Puffin, Puffin Island, June 2016.

The Puffins on Puffin Island are noticeably warier than those on the nearby Skelligs, almost certainly because they are so accustomed to human visitors there.

Atlantic Puffin, Puffin Island, June 2016.

Puffins can be aged by the number of grooves on the bill, particularly the upper mandible. By their third year, they have one and sometimes a poorly defined second, and after their fourth year, when fully adult, they have two or three grooves. Also, the red of the bill in mid-summer is bright crimson on adults, more subdued red on younger birds. The bird below is an adult at least 4 years of age. They can live to be 20 years old, though the oldest yet recorded was 36 years of age in 2007 (see here).

Three grooves on the red of the upper mandible make this a fully adult Atlantic Puffin, at least in its fourth summer, Puffin Island, June 2016.

Most of the eastern and northern slopes of the island are dominated by Manx Shearwater burrows and walking can be tricky in places, with the ground honeycombed by their burrows.

The entire eastern side of the island is honeycombed with thousands of Manx Shearwater burrows.

The 40,000 or so individual Manx Shearwaters which nest on the island are either feeding far out to sea or incubating eggs deep in their burrows during the day.

Other species which nest here are a few hundred pairs each of Kittiwake, Razorbill and Guillemot, several pairs of Chough, and up to 5,000 pairs of Storm Petrel. Source BWI

Rock Pipit and Wheatear are the two common passerines on the island.

There has been a Mink on the island in recent years, photographed by a visiting Dutch photographer in summer 2010, though an effort to keep the island predator-free has been made by BirdWatch Ireland, with some success. A single male Mink was trapped in 2011 and though none have been recorded since, there is a need for constant vigilance as this voracious predator would play havoc with burrow-nesting birds. Mink have been reported recently on at least two of the larger Blasket islands, Great Blasket and Insishnabro, and the ramifications of this are serious, as it involves multiple sightings of several individuals. Mink are good swimmers, so it would seem nearby Inishvickillane could also at risk. Attention urgently needs to be paid to eradicating it from the island group.

There are occasional trips around Puffin Island which can be arranged from Glen Pier, near Finian's Bay, or from Portmagee.

Sunday, 12 June 2016

Greylag Geese in summer

Following on last years' post on Greylag Geese breeding in Kerry, a check of the same site in south Kerry saw 9 adults, though no sign of chicks, though it is possible there are a few other females still incubating and well-hidden somewhere nearby.

Greylag Geese, south Kerry, 8th June 2016 (M.O'Clery).

Greylag Geese, south Kerry, 8th June 2016 (M.O'Clery).

Details on last years' breeding Greylags can be seen on this page HERE

Tuesday, 7 June 2016

Mergansers in Kerry in summer

First-summer male Red-breasted Merganser, south Kerry, 5th June 2016 (M.O'Clery).

Though the reddish head and neck are features of a female Red-breasted Merganser, this is actually a first-summer male, as confirmed by the black back and the two white flank spots - the beginnings of adult male plumage.

First-summer male Red-breasted Merganser, south Kerry, 5th June 2016 (M.O'Clery).

Though Red-breasted Mergansers are regular in small numbers in winter in Kerry at sites such as Dingle Harbour and Tralee Bay, they are decidedly rare in summer, and breeding has not been proven in the county for many years. This bird was at an inland lake in south Kerry, but there was no sign of a partner.

Adult male Red-breasted Meganser, south Kerry, 5th June 2016 (M.O'Clery).

Above is a different - fully adult - male Red-breasted Merganser, present at a coastal site just a few miles away from the first. Again, though they have occurred occasionally in summer at this site, breeding has not taken place in recent years. The 1969-72 Atlas shows 27 10km squares in Co. Kerry where this species bred, but unfortunately it seems that it can no longer be considered a breeding species here.

Adult male Red-breasted Meganser, south Kerry, 5th June 2016 (M.O'Clery).

Sunday, 22 May 2016

Human disturbance causes failure of two White-tailed Eagle nests

Dreadful news, that two White-tailed Eagle nests, one near Killarney and one at Mountshannon (which has produced chicks in each of the last three years), have failed due to human disturbance. 

Adult White-tailed Eagle, Kerry (M.O'Clery).

Despite the vigilance of interested locals, it is believed kayakers and possibly a drone may have been responsible for the disturbance and abandonment of the nests. The story can be read on the Irish Times website HERE.

Adult White-tailed Eagle and Hooded Crow, Kerry (M.O'Clery).

Monday, 9 May 2016

Saturday, 7 May 2016

New shrew invader on its way to Kerry

A new species of mammal is on its way to Kerry and the implications for native raptors and small mammal species is likely to be profound.

Greater White-toothed Shrew (Rasback Wikimedia Commons).

Greater White-toothed Shrews were discovered in Tipperary in 2011 and are spreading at an average rate of 5.5km per year, more than twice that of the Bank Vole. The western edge of their range is now only about 30-35km from the Kerry border, which will mean they will arrive in the Kingdom in as little as six years. 

This is also assuming there isn't a 'jump' in the range. The map below shows two established outlying populations of the shrew, one in Monaghan and another to the NW of Cork City. These were most likely from small numbers of shrew transported accidentally from the core range in Tipperary. This could happen again anywhere in Ireland and in any case, it has been estimated that the invader will spread to the whole island of Ireland by 2050. Like it or not, it is here to stay.

Range expansion of Greater White-toothed Shrews in Ireland, to 2013. There are two outlying established populations in Monaghan and Cork city, though a third, to the west of Limerick, and only 15km from the Kerry border, died out shortly after its discovery in 2010  (McDavitt, et al, 2014)
You can click the map above for closer look.

Pygmy Shrews have been disappearing wherever the White-toothed Shrew invades, and numbers of Wood Mouse have been decreasing. Raptors are feeding voraciously on the new mammal and though it was thought that it might have a positive effect on raptors, offering an abundant new food source, there have been issues with e.g. sickly and underweight Barn Owl chicks which are fed on a diet of these new mammals. The full effects of the invader are as yet unknown, but it is on its way, and here to stay, whether for good or bad.

See more on this on the Irish Raptor blog HERE.

Citation: McDevitt AD, Montgomery WI, Tosh DG, Lusby J, Reid N, White TA, et al. (2014) Invading and Expanding: Range Dynamics and Ecological Consequences of the Greater White-Toothed Shrew (Crocidura russula) Invasion in Ireland.

Thursday, 5 May 2016

New Barn Owl takes over

There has been an interesting footnote to the story of the veteran male Barn Owl, found dead on the Tralee Bypass last November (you can read the story in this post HERE). A visit to the nest site near Tralee today found a new male Barn Owl has taken over the reins at this traditional nest site, perched on the same beam outside the nest box, in an old stone barn.

Male Barn Owl, near Tralee, 5th May 2016 (M.O'Clery)

You can read more on the Irish Raptor Blog HERE.