Its been a while since I blogged about anything to do with the island and with the weather looking increasingly unsettled over the next few days, now seems like as good a time as any.
The breeding season is well and truly wrapped up and as such attention turned to migrant waders and summering spoonbills. The island did not disappoint, with some aggressive management of the water levels the island is a hotbed of migrant waders with the period from late July to August producing a good sprinkling of scarce waders and some very good numbers of common waders.
The first returning spotted redshanks and curlew sandpipers where recorded on the 23rd of July with 3 stunning summer plumage spot reds and 1 curlew sandpiper. Curlew sands have then been almost daily throughout the period with numbers peaking at an impressive 25 in early September. The first little stints appeared on the 21st of August with numbers peaking at 7 on the 23rd of August. Ruff passage has also been impressive, normally a rare bird on the island 3 have been summering on main lagoon. No doubts as a consequence of the dry conditions at other wetland sites. A personal highlight for me was a Green sandpiper on Belpers on the 22 of July, followed by three flying over on the same date.
Numbers of avocets have been steady at well over 600, along with over a 100 dunlin, over 300 redshanks, over a 100 black tailed godwits and scatterings of greenshanks, ringed plovers, sanderlings (another normally rare bird on the island) and bar tailed godwits. The first Snipe was flushed the other day and Common Sandpipers have been present throughout August.
The summering flock of Spoonbills took some time arriving, with numbers building up slowly from the 13th of July 2011, staying at 12 throughout late July and early August before peaking at 18 on the 23rd of August, soon after the flock relocated to Orfordness, leaving us with only two.
We’ve had the first scattering of passerine migrants with yellow wagtails passing through the island, the first wheatears, a Sedge warbler (the 1st for 5 years) and Chiffchaffs and Willow warblers.
A sure sign of the season changing is the arrival of a Kingfisher and the first wintering Robin, in addition Wigeon’s, Teals and Pintails have all started to build up on main lagoon. An unexpected highlight last week was a little gull, the first for three years and only the 26th ever record for the island.
It’s been a busy time for visitor events on the island with two open weekends and the Havergate adventure all taking place in August. All can be considered more or less a success, with over 500 people enjoying a trip out to the island over all the events. The Life+ project has also continued unabated with numerous visits from contractors and design consultants as we move inexorably closer to work starting in October.
It’s not often I get the chance to visit Havergate, so I jumped at the chance to help with this weekend’s event. In fact, it was my first visit for more than four years!
Havergate is an amazing place. The saline lagoons are already heaving with wading birds, and the saltmarsh is ablaze with the purple flowers of sea lavender.
But it’s the brown hares that attract the most attention. They must be among the tamest in the country. The best area is among the gorse close to the volunteers’ chalet, and on our visit today they were particularly obliging – as can be seen from the photos below.
The highlight on the lagoons was the flock of eight spoonbills on Main lagoon, though typically they spent most of their time asleep. Up to 200 avocets are already using the lagoons, alongside flocks of curlews, redshanks, oystercatchers and dunlins.
Among the dunlins, I picked out a curlew sandpiper and three knots, all mainly in summer plumage. On Cottage Flood we saw a few summer plumage turnstones alongside flocks of common and Sandwich terns, and a greenshank, but no sign of Kieren’s spotted redshank from earlier.
The island’s nesting barn owls remained asleep but while watching a distant marsh harrier it was mobbed by a large falcon: a peregrine. Superb.
All too soon it was time to return to the jetty where Kieren and Aaron were just arriving with the next group. The return journey on October Storm was accompanied by fishing flocks of terns. Hopefully it won’t be another four years till I return.
The results are in, 99% of all birds have fledged and after a changeable summer, the 2011 Havergate island breeding bird story is ready to be told.
The final counts of the large gulls where 460 herring gulls and 1030 lesser blacked backed gulls, a grand total of 1490 large gulls, how does this compare to last year? In 2010 552 herring gulls nested on the island and 1169 lesser black backed gulls. Lesser black backed gulls continue to decline on the island and after a couple of years of growth the herring gulls have fallen away, this is the first overall fall in the gull population since 2009 but lesser's have not dipped below a 1000 for the first time since 2007.
Productivity results of the gulls was also interesting (this is the measure of how many young where produced per nest). Overall across the island herring gulls performed marginally better producing 0.57 young per nest compared with 0.50 young per nest for lesser black backs. Last year both species where down at 0.35.
Visitors to the island will be familiar with the gull colony along the shingle bank, this area proved the most successful of all the gull colonies, producing a staggering 1.61 (herring gulls) and 1.58 (lesser black backs) young per nest. The Doveys lagoon powerhouse produced a respectable 0.85 (herring gulls) and 0.86 (lesser black backs) young per nest. Less successful was the salt-marsh colonies which produced on average for both species 0.41 young per nest.
How did the other key species on Havergate fare? Well, it was a mixed summer. The common terns produced only 4 young from 34 nests. A productivity of 0.11. In many ways its hard to know how to feel about this, it is very disappointing that we didn’t get close to last years figures of 11 from 29. However, the four this year where produced in a normal time frame, by this I mean unlike least year which where produced exclusively by re-lays, these where laid in late may and fledged in early July, we can therefore rightfully think of this as a Havergate island colony. However, the relative paucity of young produced suggests that we will have to cross our fingers again to see if they return next year.
Common gulls produced four from 19 nests, one less than last year and a productivity of 0.21. A slightly disappointing return, and one down from last year from one more nest. There would seem to be other factors at play here, other than just predation, possibly a food issue may be depressing production. The gorse should offer a natural protection against predation but often young do not seem to make it, at least two chicks possibly more died of starvation this year, allied with one having a leg injury making it a difficult year for the common gulls.
However, if we compare both common terns and gulls productivity from this year with the desert years of 2005 to 2009 where no young where produced at all, it has still been a good year.
Only 3 avocets pairs bred this year (producing no young) and 2011 may well mark the final year this species nests on Havergate, better news was had from oystercatchers which produced 1 young, the first in a very long time. Ending on a positve note, the Barn owls produced two young, making it a grand total of 6 young produced in 3 years.
The weather finally took a turn for the better on Havergate this week after what seemed like almost daily thunder showers, lightning strikes, torrential downpours and a nagging wind.
Now as the season starts to enter its final lap we can start to make some early estimates on how things have gone.
There are quite literally hordes of large gull chicks on the island. Ranging from small to almost fledgling. It seems the low levels of disturbance and lack of predation is to the gulls liking and despite nestingnumbers falling away slightly on the island they continue to do extremely well in terms of producing young. In the next couple of weeks we will do the chick counts and from there we will be able to establish a productivity figure.
Things are not quite as rosy for the Greater black backs where the pair in main lagoon either failed or where predated at an early stage. The pair in Doveys held territory but it is unclear whether they bred or not.
Common gulls; it is possible that some are hiding in the gorse and I am unable to see them but it seems that common gulls will not do as well this year as they did the year before. There are currently 3 big chicks spending their time loafing on the saltmarsh whilst the rest of the colony is worryingly quiet. There can be no doubts that predation pressure will have had an effect on some of the chicks. However, the gorse should offer a natural protection against the gulls, there appears to be a food issue for the adults to contend with, a couple of biggish chicks (well over a week old) have been found dead within the gorse. The best strategy appears to nest in gorse and after 10 days or so take the chicks down to the salt marsh and essentially let them feed themselves on invertebrates and scavenge the shoreline.
Common terns; optimism was extremely high last week but as large gull predation pressure has stepped up there has been a noticeable decline in the number of chicks. As an estimate I would say a half of all chicks have gone in the last week. One would expect a decline in the number of chicks at about this time as 2nd and 3rd hatchings die off unless its an exceptional year for sandeels. However, losses have been much higher than can be accounted for just by this. However, there are least 7 or 8 big chicks on the lagoon who may in fact be at the stage where they can expect not to be taken by gulls.
Avocets did eventually breed on the island but only in low numbers (3), one pair abandoned, one pair failed (presumed predated) and the final pair is still sat on eggs. Oystercatchers have fledged one chick at least, which is something of a red letter day for this species on Havergate it has been many years since this species recorded any success.
The big summering flock of Spoonbills have yet to arrive but waders are starting to pass through with numbers of redshanks and Lapwings beginning to build up.
By mid June the results of the breeding season start to come in, although how successful it proves to have been in terms of chick production will have to wait for next month.
Starting with the good news Common Terns continue to strengthen there foothold on the island with the colony increasing from 29 pairs in 2010 to 35 pairs this year. For those not familiar with the story of the terns on Havergate they reached a nadir in 2009 when only 2 pairs nested across the island. This situation was only ameliorated by a stroke of luck last year when inexplicably 29 birds arrived extremely late (early July) and proceeded to breed with a degree of success. These successful birds have made up the bulk of our returning colony this year.
Common Tern chick
Common gulls continue to breed in good numbers and help Havergate maintain its position as the largest common gull colony in the south east of England. This species was up by 1 on last year from 18 to 19. The largest the colony has been since 2008 and nudging us ever closer to our management plan total.
It doesn’t really feel like good news when one considers the history of the island but avocets continue to have a foothold on the island with 3 pairs nesting in and around the tern colony this year. In all reality these birds are likely to be failed breeders from other sites who are having one last throw of the dice this season. Whilst this is down on last year and continues the trend of avocets becoming an ever scarcer breeding bird on the island. For a long time it looked like we would have no avocets for the first time in a long time, so lets celebrate what we do have.
Now the bad news, though much depends on your attitudes towards large gulls but both lesser black backed gulls and herring gulls have declined this year.
Indeed lesser black backed gulls have dipped below a thousand breeding pairs (991) for the first time since 2007.
After their huge increase from 330 to 550 pairs in one year herring gulls have settled down to 492 pairs across the island. This means that the complete large gull population (both lesser and herring gulls) has declined overall for the first time since 2009.
Jane and Geoffrey surveying the gulls
The decline in both species specially the lesser’s is likely to reflect national trends, herring gulls the picture is not quite so clear as it bouncing around all over the place and has been for the last three years. What does seem likely, though perhaps I shall be proven wrong next year is that the era of the exponential growth in the large gull population is over.
Oystercatchers have declined to an all time low of 16 pairs nesting. Years of gull predation is likely to be driving the population down and Mallards, Shovelers and Tufted Ducks maintain little more than a toehold on the island. What is perhaps more surprising though is that Canada geese have declined by 8 pairs and are down to 44. Though we have had the bonus of prospecting swallows and singing whitethroats this year, along with red legged partridges, pheasents and a pair of moorhens
This wraps up the breeding season surveys. Most species are feeding chicks of various sizes some of the large gull chicks are big to small tern chicks which are just starting to hatch. The wet weather is a concern as this is not ideal weather for young chicks, a lot will now depend on the attentiveness of the parents and predation is always an issue.