22 July, 2010
Having missed an update last week I have to report on rather a lot so will try to be as succinct as possible. The major event recently was the strong winds and high tides of 14th and 15th July. The overnight tide and gales during the early hours of 15th July threw waves across the top of some of both South and North Islands in the lagoon and wiped out a total of three broods and seven nests of Common Tern, plus a few very late Black-headed Gull nests. The combined height of the tide and waves reached over 5.4 metres in places, and is unprecedented during the last five years of our wardening. All of the ‘top’ areas of both islands are over 5.2 metres (most are considerably higher, notably the new shingle recharge area) and would not have been inundated under any of the high spring tides that I have recorded in recent years. The timing of the stormy conditions could have been a lot worse of course, as an earlier event could have wiped out many more small tern and gull chicks and nests. Overall it has already been a very good season for Common Tern and Black-headed Gull breeding success. Exact numbers will follow in due course but it is likely to be at least 1:1 productivity (i.e. averaging at least one fledged young per breeding pair) for each species.
Predation of tern chicks has continued and sadly two broods that survived the storms of last week have now disappeared. Continued predation by Mediterranean Gull is the likely cause. One brood has appeared since then, at the southern end of South Island. These are likely to be the last new chicks we see on the reserve this summer. As is typical the first egg hatched a day before the second and until the second egg hatched the female looked very uncomfortable trying to incubate egg and brood chick at the same time. The male soon came in, passed a tiny fish to the female. She then fed the new chick for the first time.
Various other very late attempts at re-nesting will probably come to nothing as the colony begins to break up. In recent days I have counted up to 130 adult and 60 juvenile Common Terns on the reserve, many of the juveniles still being fed by their parents but still returning occasionally to their nesting territory on the islands. As time moves on more will remain in the harbour, some on the shingle spit to the south of the lagoon, before finally dispersing more widely. In the meantime the recent increase in display and territorial activity by some of the adults provides an opportunity to observe all stages of the breeding cycle in one quick scan with binoculars! I might add that the sheer spectacle of watching terns flying within metres of you as they pass between harbour and lagoon continues to be a delight to watch. The photographic opportunities are limitless too (the images below were taken with an 85mm macro lens!!).
Having missed an update last week I have to report on rather a lot so will try to be as succinct as possible. The major event recently was the strong winds and high tides of 14th and 15th July. The overnight tide and gales during the early hours of 15th July threw waves across the top of some of both South and North Islands in the lagoon and wiped out a total of three broods and seven nests of Common Tern, plus a few very late Black-headed Gull nests. The combined height of the tide and waves reached over 5.4 metres in places, and is unprecedented during the last five years of our wardening. All of the ‘top’ areas of both islands are over 5.2 metres (most are considerably higher, notably the new shingle recharge area) and would not have been inundated under any of the high spring tides that I have recorded in recent years. The timing of the stormy conditions could have been a lot worse of course, as an earlier event could have wiped out many more small tern and gull chicks and nests. Overall it has already been a very good season for Common Tern and Black-headed Gull breeding success. Exact numbers will follow in due course but it is likely to be at least 1:1 productivity (i.e. averaging at least one fledged young per breeding pair) for each species.
Predation of tern chicks has continued and sadly two broods that survived the storms of last week have now disappeared. Continued predation by Mediterranean Gull is the likely cause. One brood has appeared since then, at the southern end of South Island. These are likely to be the last new chicks we see on the reserve this summer. As is typical the first egg hatched a day before the second and until the second egg hatched the female looked very uncomfortable trying to incubate egg and brood chick at the same time. The male soon came in, passed a tiny fish to the female. She then fed the new chick for the first time.
Various other very late attempts at re-nesting will probably come to nothing as the colony begins to break up. In recent days I have counted up to 130 adult and 60 juvenile Common Terns on the reserve, many of the juveniles still being fed by their parents but still returning occasionally to their nesting territory on the islands. As time moves on more will remain in the harbour, some on the shingle spit to the south of the lagoon, before finally dispersing more widely. In the meantime the recent increase in display and territorial activity by some of the adults provides an opportunity to observe all stages of the breeding cycle in one quick scan with binoculars! I might add that the sheer spectacle of watching terns flying within metres of you as they pass between harbour and lagoon continues to be a delight to watch. The photographic opportunities are limitless too (the images below were taken with an 85mm macro lens!!).
Apart from a few newly fledging juvenile Black-headed Gulls, and some older juveniles remaining on the islands, there are now only three smaller gull chicks left. I will continue watching these to (hopefully) add them to the overall figures when they too fledge. There's been a noticeable recent increase in territorial activity with some of the remaining adult gulls re-affirming territories for next year I, with the camera capturing some interesting freeze-frame motion shots of their posturing!
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It’s not been so good a season for Oystercatcher or Ringed Plovers, with the latter failing to fledge any youngsters and the former only one. This is the latest image of the juvenile Oystercatcher; it is still being fed worms by its parents, but for the last couple of weeks it has learnt to wash them free of mud for itself (previously the adults were only presenting it with pre-washed worms!).
As the season also draws to a close out on the main Langstone Harbour islands the success of the Little Terns out there is being indicated by the regular appearance of small numbers of juveniles accompanying some adults at the Oysterbeds. Encouragingly these birds have “found” the new shingle area at the north end of the reserve and are currently using it as a loafing site at high tide. I counted a maximum of seven juveniles and four adults the other day. Just in case there is any doubt as to the differences between juvenile Little and Common Terns two instructional images appear below. In fresh plumage juvenile Little Terns have bold dark inner markings on their pale upperpart feathers (much like juvenile Sandwich Terns do) whereas Common Terns, although more variable, have narrower and more regular “sub-terminal” markings and buffy edges to the same slightly darker feathers. Of course, size is an indicator too, with Little Terns really being…. little!
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