Sunday, 30 May 2010

Attenborough CES, Visit 4

We started in bright sunshine and with a moderate breeze, the sun stayed pretty constant but the breeze increased considerably. Despite this we ended with over 50 birds including 11 retraps. The first 3J Chiffchaffs of the year were caught along with a sprinkling of other juveniles of resident species and the first Treecreeper of the year. Ominously the residents of the tit boxes have started to fledge so the next session may be busy!
Kev

Friday, 28 May 2010

Drama in Harby

This Sparrowhawk just caught a Collared Dove against the window within inches of my face! It then hopped across the road a bit and only flew off (with difficulty) when a cat approached to investigate...
Pete

Thursday, 27 May 2010

High-rise housing

Just been in Stathern checking boxes and ringed 2 Tawny chicks in a Barn Owl box that was fixed to the side of a telegraph pole. On top of the same pole was an old square Barn Owl box containing a Kestrel on 4 eggs just a few feet away!
Pete
PS Tawny nest contained an FM Song Thrush chick and 3J Starling but no mammal remains.

Dunnock nest

A great set of three pics from Mick P charting the progress of a Dunnock nest. Mick's being all humble and sending me photos 'only to put on if you think they are worth it'. Of course they are worth it Mick. Dunnock nests aren't always easy and I bet there are several group members who've not even seen one, let alone taken pictures at several stages. Consider your trumpet blown Mick!
17 May
24 May
26 May - when ringed

SNRG on the radio...

And not once, but twice in the last few days. Louise was on BBC Radio Nottingham this afternoon talking about the nestboxes at Brack and on Monday Libby was on discussing her project 'Nottingham Plan Bee'. Better go and investigate on iplayer...

Wednesday, 26 May 2010

Attenborough CES, visit 3, Sun 23 May

Only about 20 birds ringed and a few others retrapped - a slow morning thanks towind and bright sun on nets, but I did top up my suntan from Israel though.
Gary

Monday, 24 May 2010

Holme Pierrepont, Sun 16 May

A somewhat belated report on the session at HPP 10 days ago. We caught 37 birds, 23 new and 14 retraps.
Mick P & Gary

Hucknall, Sat 22 May

Good to catch several Whitethroats this morning including these two males. Note the eye colours, 6M on left, 5M on right. The 5 was also aged using the amount of abrasion on the primary and tail feathers which were very obviously inferior feathers to the adult.
Mick P

Carrion Crow nest

Below are some pics of a Carrion Crow nest I've been monitoring, from eggs through to FS when I ringed them.
Mick P

RBOP blog

Many of you know Howard and he now has a blog:
http://blog.rushcliffebarnowls.co.uk/

Tuesday, 18 May 2010

Pied Wags

They're back nesting in our school courtyard. Ringed the brood of 4 lively FM chicks with the whole of Year 6 looking through the window and two children farting their way through a trumpet lesson within feet of the nest. Parent birds not in the least bothered.
Pete

Monday, 17 May 2010

Tawny overview

Having completed the first checks of our 92 Tawny Owl nest boxes in south Nottinghamshire.  The situation here is that 23 of our boxes have Tawny Owls in them this year.  Of these:
  • female was sitting tight in 5 boxes
  • 4 boxes had 1 pullus
  • 3 boxes had 2 pullus
  • 2 boxes had 3 pullus
  • 7 boxes had 2 eggs
  • 2 boxes had 1 egg
Of the remainder of the boxes:
  • 11 had Jackdaw
  • 8 had Stock Dove
  • 1 Great Tit
  • 21 squirrel
  • 28 were empty
Several Tawnys have since failed and there was little evidence of mammal remains, but some birds.
Jim

Saturday, 15 May 2010

Tawnys

It's not been the most inspiring Tawny season so far and perhaps of note is that almost every occupied box I've checked contains bird remains, but very few small mammals. So much for supposedly being at the top of the mammal cycle this year. I wonder if the hard winter has had an effect? Two boxes have had bits of Magpie in too.
Pete

Wednesday, 12 May 2010

Hard to Swallow?

Just caught a Swallow in Caythorpe that was ringed by Jim in Flintham in June 2008!
Mick P

Monday, 10 May 2010

Attenborough CES, Sun 9 May

Visit 2 saw us catch 49 birds, all the usual warblers along with 21 Long-tailed Tits. It was a shame the cloud that came over for the afternoon was not there in the morning as most of the nets were lit up by the sun.
Kev

Sunday, 9 May 2010

Holme Pierrepont, Sat 9 May

In the end, the weather was better than predicted and the temperature climbed higher than the last few days, although it was still a bit gusty and the catch was perhaps lower than it could have been. We were greeted by flocks of Swifts which seemed to be around for much of the morning. There was also a Grasshopper Warbler reeling in the elder at the ringing base, although it never reappeared after first light.
We finished on 37 birds, most of which were Reed and Sedge Warblers. Furthermore, we had females of both with brood patches that were virtually scoring 3, so they have not wasted any time. We also caught a control Reed Warbler (proudly presented below by Archie).
We also caught Whitethroat, Blackcap and Willow, several Reed Buntings and a few other regulars.  
The occasional Yellow Wagtail flew over, a few Swallows and a single Sand Martin, some amorous Gadwall, a couple of Oystercatchers and a couple of Buzzards were all noted. A single Cuckoo called a few times. The first Common Blue Damselflies were about, as were good numbers of St Mark's Flies, but bug of the day, without a doubt, was the Green Longhorn Moth (Adela reaumurella). We found a gathering of perhaps 40 of these, dancing up and down in dappled shade, showing off their ridiculous SW radio aerials.
Pete

Tuesday, 4 May 2010

First Attenborough CES session - 1 May

The first CES visit on Sunday was carried out in windy conditions that made the prospect of a good catch remote. We did manage 36 birds though including Blackcap, Chiffchaff, Garden, Willow and Reed Warblers, some of them wearing rings from previous years. The next visit is planned for this coming Sunday.
We had some good opportunities to compare brood patches. See pictures below for good examples of the three main stages:
BP2 - bare, full of blood vessels, but muscle and gut still visible
BP3 - skin opaque, thickened and engorged
BP4 - breast and gut visible again, skin with many thin wrinkles.

Monday, 3 May 2010

Lapwing chicks

First Lapwing chicks scurrying about in Harby today.
Pete

Songbird predators on trial again...

I suspect this might get wider coverage elsewhere, but it is important for us to be informed as we have contact with many folk. From personal experience I know this is a very popular topic with landowners when checking big boxes. Anyway, have a read - it's from the latest Notts Birdwatchers Newsletter.
Pete

Magpies, Jays & Grey Squirrels
by David Parkin
A question that birders often get asked is whether Magpies are killing all the garden birds. Certainly, there has been a marked increase in predators like Magpies, Jays, Carrion Crows and even Great Spotted  Woodpeckers, all of which are not averse to taking eggs or chicks out of their nests. And then there are Grey Squirrels: they may be cute, but don’t they take nestlings too? And what about Sparrowhawks taking Greenfinches off the bird table? There is no doubt that all of these predators have increased in recent years (perhaps as the number of active game-keepers has declined) at the same time as there have been serious declines in many of our common small birds. Several studies have tried to unravel the relationship between
song birds and these predators. In general, these have suggested that, while Sparrowhawks (for example) certainly do kill a lot of small birds, they do not seem to be directly responsible for the declines in (say) Tree Sparrows or Skylarks, and, despite the loss of nests in our gardens, predators like Jays and squirrels probably do not have a major impact on Blackbirds and Song Thrushes. Cats, and perhaps cars, may be much more significant.
However, there are many who disbelieve these findings, advocating a reduction in the number of raptors, arguing that they are seriously affecting their prey species. One particularly vociferous organisation is Songbird Survival, a charity that actively lobbies for reducing (killing) Sparrowhawks in particular. In an attempt to understand the relationship between songbirds and their predators, Songbird Survival financed a study by the British Trust for Ornithology (BTO) that sought to establish the facts. The BTO is an organisation that gathers
and analyses bird data, usually by harnessing an army of volunteers who go out into the countryside to undertake surveys like the Common Bird Census (CBC), the Breeding Bird Survey (BBS), the Wetland Birds Survey (WeBS), the Nest Record Scheme (NRS), as well as supervising bird-ringing and a host of other activities. Many Notts Birders will be involved in some of these activities. The BTO strives (and I believe succeeds) in being objective: putting it crudely, they get paid at the end of the month whether Sparrowhawks take Greenfinches or not.
Songbird Survival paid for a huge analysis of the relationship between the number of passerines and their predators, using data collected through the CBC and BBS since 1967. If an increase in predators is resulting in an increase in the predation of small birds, we might expect to see correlated changes in the number of predators and prey over time: in years when predator numbers were high, prey numbers should be low, and vice versa. Using data collected by BTO volunteers from England, the scientists examined the relationship
between the number of birds and two kinds of predator: those taking prey from nests (Magpies, crows, Jays, Great Spotted Woodpeckers and squirrels) and those taking adult birds or juvenile after fledging (Sparrowhawks, Kestrels and Buzzards). Using a set of very complex statistics, they looked for associations between the number of each predator and 29 species of actual or potential prey, ranging from Lapwings and Green Woodpeckers to Blue Tits and Yellowhammers. Because CBC and BBS data are gathered in different ways, they analysed the results from the two surveys separately.
The BBS has only been running since 1995, so the data are rather limited, and the number of results that were statistically significant was pretty close to that expected by chance. Of the seven most robust results, there was a small negative association between Grey Squirrel and Greenfinch, and a slightly larger one between Buzzard and Goldfinch. While one might expect that squirrels predate Greenfinch nests, it seems unlikely that there is much interaction between Goldfinches and Buzzards, and this finding must be due to statistical chance. The remaining robust results were all positive, and mostly involved Greenfinches which increased in frequency in common with Jays, Carrion Crows and Great Spotted Woodpeckers, suggesting that these were all responding to some similar environmental effects.
The CBC data extended over 34 years (1967-2000) so provide rather more robust results. Using these data, they found several associations; nine of these were negative where predators and prey moved in opposite directions, and 21 were positive where predators and prey increased or decreased together. The strongest results were a negative relationship between Sparrowhawk and Tree Sparrow, and to a lesser degree Lapwing, Bullfinch and Reed Bunting. Negative associations were also found between Kestrel and each of Lapwing, Starling and Tree Sparrow. However, increasing Sparrowhawk numbers appear to be associated with increasing numbers of Robins and Yellow Wagtails, and to have no effect at all on species like tits,
thrushes and warblers, all of which feature regularly in their diet. When they combined the results across all prey species, they found a negative relationship for both Sparrowhawk and Kestrel, but positive for the others; this result implied that if the predators doubled in number, the number of prey would reduce by about 1% (Kestrel) and 2% (Sparrowhawk). Such changes would be swamped by the effects of altered land use, climate and habitat.
It is, however, interesting that the changes were more pronounced in the CBC data, which come from an earlier time when the environment and its avian populations were changing rapidly. Now that things have stabilised a bit, the BBS data indicate that even these slight predator-induced changes have slowed down or stopped. Overall, it seems that the widespread decline in songbird numbers is not due to predators, but more likely to agricultural and climate change and our own destruction of the natural habitat of lowland England.

Ref:

Newson, S.E., Rexstad, E.A., Baillie, S.R., Buckland, S.T and Aebischer, N.J. 2010. Population change of avian predators and grey squirrels in England: is there any evidence for an impact on avian prey populations? Journal of Applied Ecology.