Sunday, February 10, 2008

finding your way back home

A report in press from Current Biology gives the first evidence that birds (in this case Reed Warblers) are able to migrate by both latitude and longitude – something called bicoordinate navigation. Determination of latitude is reasonably easy, as orientation can be performed using either stellar or magnetic clues; but longitudinal orientation requires input of ‘time’ in some form.

Using Reed Warblers, as they are night time migrants and thus do not rely on visual clues, researches caught and displaced birds on spring migration from Rybachy to Zyenigorod (1000km east). Transporting the birds by air and mapping both geomagnetic field intensity and inclination (parameters of the earth’s magnetic field) they were able to show via caged experiments that the birds were able to orientate themselves onto a course that would take them back to their original destination; and they would not just follow a similar bearing to the one they were taken from i.e. on a course parallel to their previous movement.

This re-orientation in order to be able to compensate for their displacement - allowing them to reach their original destination - indicates that the birds can perceive longitude. How they do this is the next question to be answered. Currently the hypothesis rests on the suprachiasmatic nucleus (couldn’t find that in Svensson!) whereby the ventral core responds immediately to a change in time, whereas the dorsal shell lags behind. Measurement of the change between these two permits calculation of both ‘home’ and ‘away’ time permitting longitude to be calculated.

Image copyright of Steve Round: www.stevenround-birdphotography.com

Wednesday, February 06, 2008

Digital One

This article was timely as it affected me too. I purchased a new bed-side alarm radio with DAB features and, while running through the range of channels available, came across - the predominant gently cooing of a woodpigeon. That’s nice and calming I thought, and left it playing for a while.Now it seems others have re-discovered it too - it was first heard as a "filler" on Classic FM's frequency before it went live. As with everything ‘birdy’ twitchers have got in on the act and sparked internet ‘twitterings’ as they try to identify the birds. The record to date is twelve.
The recording was originally made in the Wiltshire garden of Digital One's chairman Quentin Howard in the spring of 1992 and has been broadcast several times previously. It now, apparently, has a loyal listening public running into tens of thousands.

How soon do you reckon before the first RSPB advert is broadcast?

Winter feeding

For the first time, scientists have produced hard evidence to show that the extra food we provide garden birds in winter makes for a more successful breeding season in the spring (as if we didn’t already know). The study from the University of Exeter and Queen's University Belfast, published today in the journal Biology Letters, compared 10 deciduous woodlands in County Down, Northern Ireland, which were either assigned a series of wire mesh feeders hung from trees and kept supplied with peanuts or left with no feed from the beginning of November to early March.

By providing similar nest box densities, and leaving some birds with extra food and leaving others to fend for themselves, the team was able to compare productivity between the two groups. Those that were given extra food laid eggs earlier and, although they produced the same number of chicks, an average of one more per clutch successfully fledged.
So what you might think. Well the authors go on to suggest that this supplementary feeding and fledging rate (plus the fact that resident birds will over-winter in a better condition) may have a
knock-on effect on other species particularly migratory species, such as willow warblers and pied flycatchers (which have seen declines in recent years) by giving resident birds an advantage.

Image from RSPB Images. Article based on one on telegraph.co.uk

Tuesday, February 05, 2008

Migratory swallow roost threatened

Wildlife Conservation Society scientists say ‘the site’ is only one of two known roosts in Cross River State, a coastal region in south-eastern Nigeria. The site is approximately two kilometers outside of Cross River National Park. Preliminary surveys by WCS indicate that the site may attract millions of swallows and be of international significance.

The roost appears to be under threat of destruction from advancing farms and may require conservation measures to survive, according to WCS, which has already contacted park officials to see if the roost can be formally protected.
The other swallow roost in Cross River State, at a site known as Boje, is considered one of the largest swallow roosts in Africa. However, it has suffered in recent years from hunting by local people, who capture the swallows for food. Still, it remains an important destination for tourists who come to see the spectacle of millions of birds gathering in a relatively small area each night.

http://www.enn.com/wildlife/article/30577

Monday, February 04, 2008

A developing strategy

I have just returned from two days at Thetford where Council and a broad section of staff undertook a professionally directed workshop examining the BTO strategy. Using the accepted SWOT analysis (strengths, weaknesses, opportunities, threats) we explored the areas of staff, members, volunteers and partner organisations to determine what were our positives and negatives.

Initially the task appeared daunting but, with help from the professionals, by the end of the two days we had managed to distil the strategy to (roughly) four points of development. A staff work group will now clarify these issues and, via a series of drafts, present the final ‘new’ Strategy to Council for ratification in July (which will be available to all members shortly thereafter).

Will this change what we do? Probably not, but what it will do is ensure we stay at the top of our game and expertise in what is a rapidly changing world with more focus, pro-active thinking and diversification of funding to ensure we maintain our independence and integrity.