Tawny Owl Treat

Participants on today's lunchtime biodiversity programme guided walk led by Allan Watson -  'Birdsong for Beginners' were treated to this fine sight from the footpath into Great High Wood.



Photo: Allan Watson


Tawny Owls are the most nocturnal of the three species of owl recorded on the University estate. Of the other two, Barn Owls are fairly regularly seen in daylight towards the end of the day and Little Owls are almost completely daytime birds.  To see a tawny owl right out in the open in full view and in broad daylight is relatively unusual.  They almost always hunt between dusk and dawn but they are recorded hunting in the open during daylight when they have young in the nest - as is the case now. (For a photo of a young tawny taken in the botanic garden, click here)

'Tu-whit, tu-who' as Shakespeare wrote in Loves Labour's Lost.  Except that William got it famously wrong. Both male and female make the typical 'hu....huhuhuhoo' call and both make a separate contact call, a sharp 'kee-wick' but neither does one straight after the other.  You might get close to the bard's description if you happen to catch a 'kee-wick' from one bird followed by a 'hoo-hoo' from the other.

However, this one did not seem to realise that we were on an aural exploration and stayed resolutely silent.

Reed-bed Birds

With Spring well and truly underway, now is the best time for seeing or hearing many of the bird species around the university. Two species currently singing from the small Reedbed by the Mountjoy buildings are the appropriately named Reed Bunting and Sedge Warbler. Several pairs of Reed Bunting, an uncommon local breeding species, have territories around the Mountjoy fields - some nesting in the scattered patches of bramble and willowherb. The unmanaged rough grassland here is a vital habitat for these breeding pairs.

Male Reed Butning. Mountjoy Reedbed

The male Reed Bunting (above) is easily identified by its black head and white moustache. One can often be heard singing its simple repeated song from the top of reeds in the reedbed. The song has been likened to a child learnng to count, but continually forgetting where it has got to and having to start again ('one ... one, two, ... one, two three, ... one, two ...').

Female Reed Bunting/ Mountjoy Reedbed

The female Reed Bunting (above) is more cryptic, and well camouflaged, looking like a well-marked sparrow, and it usually requires sharp eyes to spot her moving through the lower level vegetation.

A Wealth of Warblers

The university estate supports a high diversity of breeding birds, including a wide range of migratory warbler species. Now is the ideal time of the year to look for these often elusive birds, as they become more obvious when setting up a breeding territory and singing.

Seven species of warblers breed on the university estate in most years, including Willow Warbler, Chiff-chaff, Blackcap, Garden Warbler, Whitethroat, Sedge Warbler and Grasshopper Warbler. Most of these species are now back from their wintering grounds and are singing around the university grounds.

Whitethroat - doing a good job of hiding its white throat.
Photo: Phil Gates

Blackcaps and Chiff-chaffs are very common around Durham this year. There aren't many sections of the University woodlands in which you cannot currently hear the rhythmical song of the chiff-chaff (http://www.rspb.org.uk/wildlife/birdguide/name/c/chiffchaff/).

Chiffchaff. Photo: Allan Watson

Similarly, most bushy areas and woodland margins have the warbling song of a male black-cap emanating from them at present (http://www.rspb.org.uk/wildlife/birdguide/name/b/blackcap).

Blackcap. Photo: Steve Willis

The populations of these two species, both of which migrate relatively short distances for warblers (most of our birds probably spent the winter in Spain or North Africa), have increased considerably across the whole of the UK in recent years.

Confusing woodland warblers

Photo by Phil Gates

A willow warbler, a migrant that spends the winter in Sub-Saharan Africa, was also noted for the first time this year on Saturday, singing by the car park of the Botanical Gardens. The willow warbler’s close relative the chiff-chaff has been heard singing around Durham for the last few weeks now. The two species, which are difficult to separate by eye, can be easily told apart by their very different songs. Click on the links below to listen to their song (click the play buttons):

http://www.rspb.org.uk/wildlife/birdguide/name/w/willowwarbler/

http://www.rspb.org.uk/wildlife/birdguide/name/c/chiffchaff/

Don’t forget to record sightings of these or any other species on the Greenspace Biodiversity link:

http://www.dur.ac.uk/greenspace/internalpartners/biodiversity/records/

Spring has sprung



photo by Phil Gates

 One swallow does not a summer make – or so the saying goes. But if two swallows do, then we’re in luck as the first two swallows were sighted around the Mountjoy Site on Saturday morning.

The two birds, one male and one female were seen flying around the top of the site. Males can easily be told from females by their much longer tails. These two birds could have spent last winter as far south as Cape Town in South Africa before travelling back to Durham.

Swifts

A pilot study of Swift nesting boxes has begun at two University colleges, Grey and Josephine Butler, this month. This joint project between Durham University, Durham Biodiversity Action Partnership and Durham Bird Club will monitor the boxes in the hope that migrating birds will breed this summer. Swifts arrive from Africa and look for nesting sites. Most make their home in roof spaces, entering through gaps in tiles or under the eaves. Others nest in the gaps in crumbling brickwork. However, they are struggling to find suitable homes in towns and cities due to the British public's obsession with home improvement.

Swifts are one of the most graceful and speedy summer visitors to Britain. They are such good fliers, they even sleep on the wing. Their wings are scythe-shaped, while their tails are forked.  They eat flying insects and airborne spiders. Unlike swallows, they never perch on wires.

We are very grateful to construction company Laing O'Rourke for assistance in erecting the boxes.

Long-Tailed Tits

These beautiful little birds can be seen all around the estate, including college grounds. They nest in woods and hedgerows where they build a luxury home for themselves and their offspring. They line the nest with up to 2,000 feathers and will fly between 600 - 700 miles searching for the best materials to camouflage it.

When the breeding season is over, they form small, sociable flocks of about ten birds, consisting of adults and their offspring. They search for food together and roost communally, huddling together for warmth.

Red Kite

Not too many years ago people would have assumed that you were mistaken if you said that you had seen a red kite over the Botanic Gardens. Not so any more, as a re-introduction programme carried out between 2004 and 2006 in the Derwent Valley just to the north of Durham, released a total of 94 birds in the project known as Northern Kites. Breeding success (the first for 170 years in the NE region) has led to birds expanding out from the Derwent Valley base and therefore we can probably assume that sightings in the skies above the University estate will continue to increase. (A release scheme at the Harewood Estate in North Yorkshire has also produced birds seen in the North East)

Last weekend Steve Ansdell was the lucky chap who watched a red kite circling high in the skies above the Botanic Gardens on two successive evenings. They are truly majestic in flight and even at a distance the profile is unlike anything else that you are likely to see. The long wings and forked tail are distinctive.

If you do see a red kite it is worth trying to get onto them with binoculars as every released bird and most of the young birds have been given a unique combination of coloured and numbered wing tags to monitor progress. The details can be found here.

Finally, if this post has whetted your appetite, there are a number of places in the Derwent valley where you will have a really good chance of seeing a red kite. There is a guide to the best viewing points here.

(Thanks to Phil Gates for the use of his library photos)

Chiffchaffs

One of the sure signs that the seasons have turned is hearing the song of the chiffchaff - the first of the incoming summer migrant warblers to arrive at the University. Walking through Great High Wood at lunchtime today I heard my first one this year, chiff-chaffing away in the shrub layer beneath the bursting horsechestnuts and the yet dormant beeches. Its about a week or two later than the first one I heard last year.


Not that long ago you could be sure that you were listening to a tiny brown bird that had just flapped its way to Durham from southern Europe or even Africa but these days you can't be too sure because the number of over-wintering chiffchaffs in the UK has been steadily increasing for some years now. There is a map here on the RSPB web site which shows the north/south divide for over-wintering and I am sure that its a fair bet that the line is moving northwards. In fact I heard one singing in the hedgerow on the east side of the Science site as late as September 29th last year.


By contrast, the willow warbler, which to look at is a dead ringer for the chiffchaff, seems to be a total migrant with no over-wintering recorded at all (map here). It will be a week or two before the first of these little birds arrives in our grounds.

Although the chiffchaff and the willow warbler look so alike, their songs are totally different. You can compare recordings of each on the two web site links.

Treecreeper

Treecreepers are beautifully adapted to hunting for small insects in the bark of trees. Those long, needle shape claws give them the grip they need to climb and hang on the underside of branches and their beak is like a long, curved pair of fine forceps. You can often see them in the Botanic Garden (where this one was photographed on an alder tree on Monday lunchtime) or along the woodland nature trail at the bottom of the garden.

In winter they are most often seen in small flocks of blue tits, great tits and long-tailed tits but from spring onwards they're more solitary. Treecreepers have a characteristic foraging strategy, starting at the bottom of the tree, working their way upwards and exploring every crevice until they're maybe 5 -10 metres above the ground then flying to the base of another trunk and starting all over again. Nuthatches tend to use the reverse strategy, often climbing down trees head-first.

Treecreepers nest behind loose bark on dead trees.

Beginner's Birds: Great Blue Coal

This mini feeding station at the rear of the Health and Safety Service building on the Science Site has attracted 14 different species of birds ( and a squirrel). These photos show the commonest 3 visitors - from the top, great tit, blue tit and coal tit.

Although these are common birds around the campus, identification does still confuse people who take only a passing interest in birds.

Here are some key identification pointers:-

Great tit: the chunkiest of the three; very bold white cheeks; strong black mark down the centre of its chest

Blue tit: daintier and...well...blue-ish on its head and back

Coal tit:: dainty - like the blue tit: white cheeks but never as clean and bold as the great tit. Also - look on the back of the head where there is an extra white patch.

Heron

You are probably most likely to spot a heron by the two ponds at the back of the Mountjoy buildings but they turn up from time to time at most of the other ponds on the university estate - in the Botanic Garden, on Van Mildert lake and Trevelyan college pond, for example. Herons are early nesters and will be feeding young in March... and the frogs that breed in all the above ponds are favourite food items. Once they find a good hunting ponds they'll return regularly, usually early in the morning before sunrise. They can spot the glint of water while flying over and that probably accounts for the arrival of the heron below on the roof of the Maths department - because there's a small pond in the courtyard next to lecture theatre CG91, just below its roof-top perch...

Photo coutesy of Michael Coxon

Photo courtesy of Stephen Applegarth

 

Photo courtesy of Stephen Applegarth

Photo courtesy of Stephen Applegarth

Kestrel

Although birds of prey are frequently seen flying over the Science Site (red kites have been seen overhead during the last couple of years) the raptor that you are most likely to encounter there is the kestrel. You'll often see one hovering over the grassland just north of Hollingside Wood, behind the Mountjoy Buildings, hunting mice and voles. From time to time they also breed in Hollingside Wood.... which is good news, since kestrels have been declining in some parts of Britain.

The little feather that you can see sticking out of the leading edge of each wing, about half way along, is the alula, which allows the bird to hang in the wind motionless, while it scans the ground below for prey. Anatomically, the alula is the bird's thumb and the feather controls airflow across the leading edge of the wing when it's held at a high angle attack, generating maximum lift without stalling. Leading edge slats on short take-off and landing aircraft serve the same purpose.

Winter Thrushes

The arrival of the winter thrushes from the far north of Europe is one of our great annual bird events. Driven south and west from their breeding grounds as the temperatures drop in the northern latitudes they arrive in the region in huge numbers, especially in colder winters like this year.

The large car park on the Science Site (on the road up to Mountjoy) has a couple of rowan trees just by the entrance and at lunchtime on the last day before the christmas holiday break they were absolutely covered in yellow berries and absolutely heaving with 4 of the members of the thrush family that can be seen in Durham during winter (fieldfare, redwing, mistle thrush and blackbird). By 5pm the trees were stripped bare and the birds long gone.

The fieldfare (above) and the redwing (below) only visit us in winter.

Although the blackbird, mistle thrush (below) and song thrush can be seen all year round in Durham, our resident birds are joined by huge numbers that migrate here, like the fieldfare and redwing, and swell the local population during winter.

The British Trust for Ornithology has tracked the arrival of fieldfares through its birdtrack scheme and published a graph for the last three years on it web site (click here). This shows a remarkable consistency in arrival dates and numbers. The peak in 2010 records coincided with my sightings in Durham.

Identification is fairly straightforward if you can get close to feeding birds or have binoculars. Fieldfares are exceptionally beautiful with distinctive grey heads. Redwings can be identified by the creamy eye stripe. They do also show a russett red patch on their sides.

The mistle thrush and the song thrush are similar but the mistle is bigger with cleaner-looking spots on a whiter breast than the song thrush.

There are size differences too if you see them together. Fieldfares and mistle thrushes are bigger and chunkier than redwings and song thrushes.