Thursday, August 18, 2011

Well Sorted

Firstly my apologies to readers for the messy appearance of the blog for the last two days when the right hand column ended up below all the posts. This was caused by the simplest of problems, a stray piece of HTML overlooked in my last post Slightly Cuckoo. In the end the post title proved more accurate than envisaged. In due course and to compensate for this dreadful mistake, more new Cuckoo pictures will follow soon on Another Bird Blog.

I fixed the Blogger glitch this morning at 5am, just before I made tracks for Out Rawcliffe and a spot of ringing. On such a fine, wind free morning I suppose Will and I hoped for a big catch this morning, the first one for some time where we could use a full spread of nets. The overnight clear skies may have moved birds on ahead of us, our excuse for not catching enormous numbers. However we achieved a great variety of birds with yet more warblers plus witnessed clear signs of autumnal visible migration with our in-between net rounds birding.

We totalled 32 birds, 29 new, 2 recaptures and 1 “control”, an adult female Chaffinch ringed elsewhere – ring number R988282 other ringer bloggers out there? New birds: 9 Willow Warbler, 6 Chaffinch, 3 Blackcap, 3 Whitethroat, 2 Tree Pipit, 2 Lesser Whitethroat, 1 Garden Warbler, 1 Robin, 1 Treecreeper and 1 Blackbird.

Tree Pipit

Tree Pipit

Treecreeper

Lesser Whitethroat

Blackcap

Garden Warbler

Our recaptures: 1 Willow Warbler and 1 Whitethroat. As we are now well into the month of August the Whitethroats moving through the site are almost exclusively juveniles, i.e. 63 of 68 Whitethroat captures in the last 30 days have been young birds of the year. That is because most of the adults migrate earlier than the juveniles, young of the year which in August can be correctly aged but not sexed. Adult Whitethroats can be difficult to accurately sex at most times, in fact it is probably impossible in the field in August when they undergo moult. We thought today’s moulting adult may have been a male, until at home a check on IPMR records from May and June showed it to be a breeding female.

Likewise, autumn Willow Warblers are difficult to age and it is only in the hand that anyone can say with certainty that an individual is an adult or a juvenile.

Whitethroat moult

Whitethroat adult

Willow Warbler

More signs of autumn appeared this morning with visible Chaffinch movement – circa 30 birds passing overhead, contact calling as they headed south, then of course the capture of another ringer’s Chaffinch. Tree Pipits also fell into the “vis mig” category with 2 caught and a minimum of 4 birds overhead. The morning also saw a marked passage of Alba wagtails with upwards of 18 individuals heading west, the appearance of more Sylvia warblers and the early morning sound of Robin sub-song, a species that proved to be first in the nets.

Other birds this morning: 80+ Swallow, 4 Corn Bunting, 4 Grey Partridge, 1 Kestrel, 2 Buzzard and 50+Goldfinch. I almost forgot – the female Sparrowhawk that flapped from the net before we could reach it. Oh well there’s always another day.

On the non-birding front, Will who is a bit of a wildlife sleuth found the footprints of a Stoat where we often see one running alongside our plot, but we didn’t see the animal today, just Brown Hares and Roe Deer.

Stoat tracks

Tuesday, August 16, 2011

Slightly Cuckoo

Sue thinks I’m daft, slightly cuckoo even for spending so much time birding and ringing, even in the most off-putting weather. But occasionally the unpromising days turn out to be actually not bad, just like this afternoon when I took a trip out Nateby way after the morning rain had cleared even though the cloud remained and the stiff breeze still blew from the west.

After many years of carefully nurturing the farmer, I am ok to take my car down his track, a ploy that worked well when I found what I thought to be the Cuckoo of last week, some way off from the original spot. The Cuckoo didn’t take too much notice of the car halfway through the field gate, enabling me to get a few more pictures

Cuckoo

Cuckoo

Cuckoo


Cuckoo

After a few minutes I realised there was actually not one but two Cuckoos, having a bit of a Barney over possession of the good feeding they had found, but keeping a respectable distance from each other until their paths crossed. The few distant shots below are the best I could get of their squabbles where they appeared to employ their red juvenile gapes in threat posturing. It’s rare enough to see a single Cuckoo nowadays so I was doubly lucky to witness this behaviour.

Cuckoo

Cuckoo

After a while I left the Cuckoos, parked up the car out of tractor’s harm and took a walk where things got even better when a Swallow hunting Hobby came close by. Not unusually it was the Swallows that drew attention to the raptor with their twittering alarm calls; I watched as the Hobby continued towards Nateby village, disrupting more Swallows feeding around the next farm buildings before it was lost to view.

Hobby

Following those events it was hard to concentrate or better the day but I also saw 6 Whitethroats, 3 Buzzards, 1 Kestrel and 80+ Swallows, then 6 Swift heading south.

Buzzard

On my way home I promised Farmer Philip a picture of the Cuckoo if there was a reasonable one. Philip hadn’t seen or heard a Cuckoo on his land for several years.

Cuckoo

Cuckoo

Sunday, August 14, 2011

Sunday Jobs

After Saturday’s disappointment Will and I promised ourselves another bash today so met up again, usual time, and usual place. As we hit the moss road at 0615 a heavy shower threatened to wipe out our ringing session: the downpour didn’t last and we soon erected just three nets in the eastern most part of our plot, mindful of the promised scattered showers and 15mph westerly for 10am.

It didn’t rain more but the stiff breeze did curtail the session early at 1030. Despite this we caught a good mix of yet more warblers and several finches, during what proved an interesting and varied morning of birding and ringing.

Our overall catch was 27 birds of 8 species, 22 new and 5 recaptures. New birds: 5 Whitethroat, 5 Willow Warbler, 6 Goldfinch, 2 Great Tit, 1 Chaffinch, 1 Blackcap and 1 Lesser Whitethroat – not only one of the smartest warblers, but the first of our year. Recaptures: 2 Whitethroat, 2 Willow Warbler and 1 Blackcap.

Lesser Whitethroat

The young Blackcap had almost dispensed with its brown cap and sported a not quite black hood.

Blackcap

Many of the young Goldfinches are now in stages of their post-juvenile moult, and with a little care it is possible to sex some of them, like the juvenile male below. Despite the lack of Goldfinch red on the face the new black nasal hairs show that this bird is a male - a female has greyer nasal hairs.

Goldfinch

Birding wise there was perhaps a little evidence of finch movements, with several Greenfinch and Chaffinch, but also 4 singles of Lesser Redpoll, all chattering south. Local Linnet and Goldfinch numbered 15 and 35 respectively. We estimated Swallows this morning at 80+, but found no difficulty in counting the single Swift that headed north about mid-morning. Otherwise, 1 Great-spotted Woodpecker, 60 Woodpigeon, 3 Buzzard, 1 Kestrel, 2 Pied Wagtail and 4 Skylark.

Sunday On The Moss

About 9am we had brief views of a cream-headed female Marsh Harrier before it flew off in the westerly direction of Pilling Moss, disturbing dozens of gulls and Lapwings from its path. Not the bird we saw here a week ago, and definitely a different bird.

On the way home I called at Hambleton to ring the penultimate brood of 4 Swallows for the year, where youngsters ringed last week now looked on the verge of leaving their stable. The final brood should be ready for ringing on Thursday next.

Swallow

I just looked outside at the lawn. With all the rain of the last week the grass really needs a cut. OK it’s Sunday afternoon when we should all take it easy, but if I go and get the job done now there are a few Brownie Points on offer for next week’s birding.

Saturday, August 13, 2011

More Water, More Warblers

Will and I met up at Out Rawcliffe this morning hoping for another decent catch of warblers to boost the already good numbers for the year. Prior to today, and after a worrying and slow start to the summer catches, our Willow Warbler total here for the year stood at 82 and our Whitethroats at a convenient and precise 100 birds.

Even this morning the rain and cloud of the past three days still hung over the moss as patches of drizzle and rain headed inland towards Bowland where the low cloud obscured the topmost fells. Watching the clouds roll in we put up a less than ideal length of netting, a strategy which proved of mixed success when we later found it easy to close the few nets for a while to let the drizzle pass over, but which resulted in a slow, interrupted and frustrating morning.

Our catch was pretty poor with just 14 new birds and 5 recaptures. New: 6 Whitethroat, 5 Willow Warbler and 1 each of Reed Warbler, Goldfinch and Blackbird. Recaptures: One each of Goldfinch, Dunnock, Whitethroat, Willow Warbler, Chiffchaff and Blackbird. The Blackbird recapture was ringed here as a nestling on 27 July, so we know that at least one of the four nestlings ringed that day survived to fledging stage.

Reed Warbler

Whitethroat

After today here our 87 new Willow Warbler catches break down to 47 adults, 29 juveniles and 11 nestlings. Whitethroat totals now stand at 106 birds - 28 adults, 74 juveniles and 4 nestlings.

Willow Warbler

Whitethroat

The poor visibility also denied us much opportunity for birding but we clocked up 80 Swallows, 8 House Martin, a post summer flock of 70 Woodpigeons, 4 Corn Bunting, 8 Mistle Thrush, 30+ Goldfinch and 17 Linnets. Looking out for raptors realised 1 Kestrel, 1 Sparrowhawk, 2 Buzzard and the inevitable Little Owl, seeing us off its patch once again.

Little Owl

If it’s fine in the morning we’ll try again.

Friday, August 12, 2011

Did You Sleep Well?

There were three words in particular that stuck out from Eno’s North West weather forecast last night, Gloomy, Damp and Heavier. The first two words are self-evident with the third relating to the intensity of droplets falling from on high. Hence I find myself sat at the PC again, thinking and blogging about birding without actually picking up my bins or pliers. In fact after recent weeks of seeing huge Swallow roosts and finding for the first time a Goldfinch roost, I found myself reflecting upon birds and their sleeping arrangements, in particular their communal roosts.

Lots of species roost communally, mostly outside of the breeding season. We have all seen evening flights of gulls heading out to sandbanks, watched massed waders on the tideline or marvelled at the acrobatic formations of thousands of Starlings or Red-winged Blackbirds at dusk. Maybe we have watched a procession of Wrens making their way into a garden nest box to spend the night, or disturbed the Blackbirds from the thick Holly bush near the front door. As a birder and a bird ringer I have been interested in roosts for a many years and both watched and worked communal roosts of Swallow, Chaffinch, Brambling, Linnet, Tree Sparrow, Greenfinch, Goldfinch, Redwing, Blackbird, Fieldfare, Pied Wagtail, Yellow Wagtail, Long-eared Owl, and various mixed wader flocks.

Chaffinch

What all those gatherings have in common is that the birds are resting, roosting and sleeping, but it is not quite the slumber we humanoids know of eight hours tucked up in a warm bed. A bird’s disturbed and restless sleep that appears to us more like a quick nap is in fact a product of their innate ability to distribute sleep between the right and left hemispheres of their brain and effectively remain awake in the other; hence the roosting bird with one eye open, head tucked in, but always alert to predators. Also, birds that roost off the ground have specially evolved tendons in their legs so that when they are on a perch and relax their legs, their feet automatically curl around the perch and hold on with a tight grip so they can sleep without falling off. It’s easy to test that function out by allowing a Sparrowhawk or Kestrel to grip a finger or other suitable part of your anatomy.

Sparrowhawk

Studies into communal roosting in birds theorise three main benefits: Guy Beauchamp, The evolution of communal roosting in birds: Behavioural Ecology (1999).

1. A reduction in thermoregulation demands, (Thermoregulation is the ability of an animal to maintain body temperature within certain boundaries, even when the surrounding temperature is very different). The presence of nearby birds in communal roosts may reduce the energy demands for thermoregulation by for instance huddling together and thereby lessening the cooling effect of wind speed or direction. My experience of winter finch and thrush roosts has shown how they favour thick evergreen bushes in sheltered spots to spend the night, but conversely Fieldfares alone amongst the thrushes seem to favour rough grassland in which to pass the dark hours. The whole idea of warding off the chill by crowding together makes absolute sense when thinking about a tightly packed flock of waders on a windswept winter beach.

Sanderling

Fieldfare

2. A decrease in predation risk. For instance, the presence of more eyes in a communal roost may increase predator detection. In addition, the sheer number of individuals using a communal roost may decrease the risk of predation to an individual bird through the dilution effect. However, the greater conspicuousness of communal roosts may mitigate against the dilution effect, i.e. we have all witnessed how large roosts attract several predators. The geometric structure of the communal roost is also thought to provide increased predation avoidance; e.g. individuals that occupy central positions in a communal roost may be buffered from predators to a greater extent than birds sleeping on the edge or higher up. Does the Sparrowhawk dive into the Swallow roost and carefully select a bird from the centre or take the first one it happens upon near the top stems or the outer margins of the reed bed?

Swallow

3. Increased foraging efficiency. Increased foraging efficiency is often considered the main advantage of communal roosting in birds, whereby a roost acts as an information centre where unsuccessful foragers can follow more successful or experienced companions to good feeding areas. Communal roosts have been hypothesized to be an accumulation of foragers spending the night as close as possible to good feeding areas, i.e. birds join large roosts to reduce commuting costs from the daily centre of activity or simply join in as they pass on migration. Observations from local roosts of Swallows and finches support this theory with the whole roosting process from start to finish taking a couple of hours as birds arrive in small groups from all compass directions before settling down for the night. Ringing recoveries from the same periods also support this theory with quite local recoveries but also birds from further afield or indeed highly migrant birds like Bramblings recruited into a large Chaffinch roost, or on other occasions Sand Martins and Yellow Wagtails joining a Swallow roost.

Brambling

Well it’s now 2pm but still peeing down and whilst the above makes food for thought, creates a post for Another Bird Blog and passes an hour or two, I’m now tired and going for a quick snooze.

Lesser Black-backed Gull

Thursday, August 11, 2011

Short Session

36 hours (so far) of rain and wind in Lancashire has meant no posts on Another Bird Blog. This morning’s rubbish weather restricted birding to an hour with the incoming tide at Knott End before the rain rushed in from the south west to send me scurrying back home. In the circumstances this is but a brief report from which there are a few good counts from the sixty minutes, but not too many bright new pictures from the grey overcast morning.

At the jetty I could see 10 juvenile Eider and 4 Cormorant loafing at the point where the construction tails off into the estuary. As the tide ran in and the 9am ferry arrived from Fleetwood the birds all took to the water, Eiders upstream and Cormorants out to the deeper waters of the bay.

A number of terns and gulls arrived on the beach with the rising tide, 41 Sandwich Tern, 4 Common Tern and 130 Black-headed Gull, where they joined 270 Oystercatcher, 2 Whimbrel, 1 Bar-tailed Godwit, 2 Knot and 7 more Cormorants. Coming from the direction of Preesall Sands I counted 1100 Dunlin, 9 Ringed Plover and 4 Golden Plover, all heading upriver to the Barnaby Sands roost.

Golden Plover

Dunlin and Golden Plover

Luckily, I got a half decent picture of a Sandwich Tern a week ago when an adult bird accompanying a fully-fledged youngster came to warn me off when I approached too close. The second picture which appears to be black-and-white was actually taken this morning in the grey, cloudy, overcast conditions. However, autumn is a great time to watch terns in the local area as they breed some distance away from the Fylde coast.

Sandwich Tern

Sandwich Tern and Common Tern

When the rain came with more force, I took to the car and sat out the rain for a while as the ever present gulls waited patiently for bread hand outs from parked vehicles. The gulls might have had a longer wait than normal today, a day for not venturing out.

Lesser Black-backed Gull

Tuesday, August 9, 2011

The White Morning

Monday night’s forecast wasn’t too promising. When I woke up and looked out the weather didn’t seem so bad, so I made a journey to Out Rawcliffe where I could have a wander about and maybe find a sheltered spot for a few nets. First off I saw the young Tawny Owl in the exact same spot of a couple of weeks ago: so was the side branch, partly obscuring the bird.

Tawny Owl

The stiff north-west breeze left a couple of spots unaffected on the east side of the plantation, so within 20 minutes of my arrival the nets were up and were operational. I stayed busy the next three hours with a good catch of mainly warblers, many of them newly arrived Whitethroats, so I reckon I hit upon the right morning. The overall catch was 29 new birds but no recaptures: 17 Whitethroat - all juveniles, 5 Willow Warbler, 2 Reed Warbler, 2 Swallow, 1 Garden Warbler, 1 Blackbird and 1 Tawny Owl.

If rough calculations are correct there are now exactly 100 new Whitethroat captures on site this year with an overall total of 128 if all the recaptures are added.

Whitethroat

Whitethroat

17 “Whites”

The two Swallows caught were an adult and a juvenile.

Swallow - adult

Swallow - juvenile

Migrating Reed Warblers turn up in young woodland growth occasionally.

Reed Warbler

The second Garden Warbler here in a week.

Garden Warbler

The second juvenile Tawny Owl of the day turned up, but this time in the bottom panel of a mist net, just a foot or two from where it flapped out of the net on two previous occasions. As I processed the downy owl, Rachel came walking by and offered to take a photograph of the still sleepy, docile creature. Thanks Rachel.

Tawny Owl

Tawny Owl

Other birds this morning: 2 Jay, 18 Tree Sparrow, 4 Greenfinch, 3 Skylark and approximately 80 Swallows. Swallow numbers seem definitely lower following the clear out of last week, and they were noticeably absent from the nearby fields and farms on such a bright, sunny morning.
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