Sunday, March 30, 2008

who pays the weatherman?

...because they should ask for a rebate. The forecast for this weekend was for nasty weather - high winds and rain. This moderated to just rain as the weekend neared and then didn't change much thereafter except the wind-speeds were reduced.
Given that the parameters were going to be outside the limits for acceptable ringing I committed myself to other things. Thus, image my annoyance when Saturday morning broke fine and sunny and today was even better (could have been ringing most of the day). The weather-person would not be a welcome visitor at the moment.
In order to work out my frustration I took a quick walk round the local park - blackbirds nesting, nuthatches calling, lots of coal tits about but no signs of any woodpeckers. A wandering male sparrowhawk put the feral pigeons to flight and the Canada Geese were as noisy as possibly laying down claims to their little bits of the pond. Eight Tufties were present, but no Little Grebe and the Coots' nest of a week ago with three eggs had been predated.
But there was good news - spring at last! - heard two Chiffchaff (hurrah) and also discovered a new species of duck on the pond (see photo).

Saturday, March 29, 2008

Other things that fly

Watchers of birds also tend to observe other things that fly - bees, butterflies, wasps, moths and dragonflies (is there anything else left?). So with as much interest as they read about the demise of birds they read about the fate of other flying species.
One piece that caught my eye today was that of a (flying) parasitic fly, Sturmia bella, affecting the life of one of our most colourful butterflies - the Small Tortoiseshell. Apparently the caterpillars of the butterfly eat the eggs of the wasp, which then hatch within the caterpillar, and feed on it as they develop into the adult wasp.
Although not proven the concept is sound, but what makes it more worrying is that the wasp is only a recent addition to our shores so, if correct, Small Tortoiseshells could be heading for difficult times.
Note - the picture is not to scale. The wasp is definitely smaller than the butterfly.

Thursday, March 27, 2008

More spuds mean more Yellow Wags

Yellow Wagtails have declined in the UK by 65% since 1970 and, according to Dr James Gilroy at the University of East Anglia, much of this decline is due to their inability to raise sufficient youngsters each year. In Yellow Wagtails the capacity to have successful second broods appears to be paramount to their survival.

On returning from Africa the birds establish territories in autumn-sown cereals and, while tending broods as the winter-wheat grows from 20-70cm, they will tolerate the rapidly changing crop. For second broods however they will look to re-nest in crops of a looser canopy.

From a study undertaken in Lincolnshire Dr Gilroy found the overall breeding success was low, with 59% of attempts failing completely. When details were taken of the crops growing in the fields in which birds were attempting to breed a pattern began to emerge. Second broods raised in potato fields did better than any other crop; increasing in importance as the breeding season progressed. Beans, peas and sugar-beet were also used for attempts but were much inferior. Set-aside and oil seed rape held no territories.

So, given our regional limits on Yellow Wagtail distribution, maybe we should be pressing for farmers to be growing more potatoes in order to secure our limited population of Yellow Wagtails.

Adapted from a BTO News Release. Image from www.shropshirebirds.com

Wednesday, March 26, 2008

Spring is springing

The Meteorological Office says that February was the brightest (109.9hrs of sunlight) since 1929, although the national mean temperature was a modest 4.9degrees. However this was still 1.9degrees above the 1961-90 average. Why is this so important? Well it precedes the March surge – when all our summer migrants start to appear. The brighter and warmer it is the earlier they appear.

Wheatears started to appear in the UK at Portland BO on the 15th March and have been passing through locally for about 8 days or so. Little Ringed Plovers have been reported on the Sefton coast, while Black Redstarts have, even by our standards, been scant. On the same day Wheatears were at Portland swallows were reported at Leasowe Lighthouse on the Wirral. Sand Martins are now arriving and the first Chiffchaffs are beginning to make themselves known.

Set against this we have Long-tailed tits incubating, herons with chicks and eggs, Mallards with young, Coot and Moorhen on eggs, Woodpigeons, Collared doves and Magpies all visibly nesting and, interestingly Pink-footed Geese, Whooper swans, Redwing and Fieldfare still with us.

The next period of Atlas recording – due to start in less than a week and supposedly the breeding component – is likely to be a joke (it starts April 1st) but, not in a humorous context, but in a perplexing one in that we will have a full repertoire or birding events going on. Winter visitors still here, summer ones arriving, some birds on eggs and others with young – I look forward to seeing all the results in due course.

Image of Willow Warbler from www.naturfoto.cz Copyright Jiri Bohdal

Wednesday, March 19, 2008

Bird song as an early indicator of species decline

Studying a metapopulation of Dupont’s Lark in NE Spain researchers have found a relationship between (individual) bird song complexity and diversity and the viability of the population as a whole. Males from the most numerous and productive populations sang songs of greater complexity than birds from smaller populations, which sang less complex songs. They argue that the cultural milieu of a large viable population, which then permits birds to learn more complex songs, creates an association between song complexity and viability of the population.

They then go on to say that this simple quantifiable measure of a vocal characteristic could act as an early indicator of a local population decline.

Citation: Laiolo P, Vögeli M, Serrano D, Tella JL (2008) Song Diversity Predicts the Viability of Fragmented Bird Populations. PLoS One 3(3): e1822. doi:10.1371/journal.pone.0001822

Image: Dupont´s Lark by Josele Saiz from www.birdingspain.com

Thursday, March 13, 2008

Godwitology

As most of you are aware, during the last two years we been focusing our studies on the wintering ecology of the black-tailed godwits at several areas of the range. During this period, the tracking of colour-ringed individuals was very intense particularly in areas where detailed information was missing, namely in West Portugal and Southern Ireland. We have also added 100 colour-marked individuals to the black-tailed godwit schemes, all marked on these wintering locations, plus several other hundreds ringed elsewhere across the range.

We now wish to unravel another question on the fascinating tale of the Icelandic Black-tailed godwits, and to do so we request your help! The question we now face is “Which migratory routes are mostly used by black-tailed godwits during spring migration”.
Our current data show that some birds wintering in Iberia and France migrate north mostly via the Netherlands, while others take another route via England. Interestingly, quite a few birds wintering in Ireland also make a westwards detour, towards England, on their way to Iceland.

These suggestions however, are extracted from a small sample, since only few godwits from these wintering locations were recorded during migration so far. As we have increased considerably the numbers of colour-ringed godwits at these winter sites, we are aiming to get more migration sightings so that a good sample is recorded. We are also organizing a trip to Iceland so that we can record the arrival of these birds, which hopefully have been seen on migration.

In order to tackle this question we ask for your help in recording the complete colour-ring combinations of any marked black-tailed godwits you might encounter during these next two months. Recording their location, moult stage (as % of breeding plumage and bill colour (% of orange), habitat used for foraging and ideally length of stay, would be very helpful for our study.
Please be aware that some of these birds have now been fitted with flags!

Several other black-tailed godwits colour-ringing schemes also use flags so it is important to note the colour and position of the flag and also the total number of colour-rings on each individual. We thank you for all your input on this project and we hope to send you very colourful life-stories of these individuals any time soon…
All the very best!
The Jadrakan Project team.
Please send sighting information to: j.alves@uea.ac.uk
Picture taken from www.birdingworld.co.uk Copyright Pat Wileman