Girton Birdwatch - September 2007
The swifts will have gone, and probably the swallows and house martins too, by the time this appears, and that will be the end of the 'summer'. At least they arrived, unlike (in my experience at least) the cuckoo and, one of my favourites, the spotted flycatcher. The latter, which used to be a fairly widespread summer visitor, has suffered a near catastrophic decline over the last twenty years or so, and is now increasingly scarce. They have been seen throughout Cambridgeshire this year but have been few-and-far-between. Nobody seems sure why this decline has occurred (as with many of our other song birds) although drought on their wintering grounds in Africa is often mentioned; our indifferent summer can't have helped as it led to a dearth of the flying insects upon which they are so dependent. The first two weeks of August saw an increase in the number of dragonflies and damselflies, the main prey of the hobby, so you might have caught a glimpse of them.
Cuckoo numbers are falling so rapidly that some authorities believe that its role as a harbinger of spring is under threat. Again, no one seems to know what's happening. Some point to the correlative decline in host species such as the dunnock (hedge sparrow) and meadow pipit, with meadow pipit numbers in particular plummeting by almost 60% over the last 30 years. Others believe that the decrease in moth populations, especially the garden tiger moth which only the cuckoo finds palatable, is responsible with the blame being placed at the door of global warming and the run of wet, mild winters which have encouraged the spread of the fungi which attack the over-wintering caterpillars. Still others suggest that, as with the spotted fly catcher, the main reason is to be found thousands of miles away with the drought in East Africa. It's probably a combination of these and other factors.
A bird which does well locally - it must be all those ornamental ponds we are building! - and which is difficult to ignore or miss, is the grey heron. I never cease to be amazed by the size and appearance of this dramatic-looking bird; surely the most pre-historic-looking (you know what I mean!) of our native species. It flies slowly, with heavy wing-beats and has its s-shaped neck drawn back, giving it a hunched appearance while its long legs trail behind. Although it gives the impression of being a solitary bird - we just tend to see the odd one around here - it is a gregarious nester forming large colonies, usually in trees but sometimes in reed beds. Because it eats fish and could seriously affect stocks, quite a lot is known about heron numbers, with census work starting as early as 1928. There are about 1,500 pairs in the British Isles and numbers stay fairly stable although they are vulnerable to harsh winters, the recent absence of which probably helps explain their noticeable presence in the village. Although they take fish - koi and goldfish included as some will know to their cost - their diet is much more varied and they'll devour water-voles, beetles, frogs, moles and rats with equal enthusiasm. John McGibbon saw one being mobbed by rooks in the village recently, which is understandable as the heron is a threatening-looking bird and not averse to taking chicks, and even their parents if of suitable size.
The heron is related to the little egret which used to be an occasional visitor to these shores but which is now almost becoming commonplace. In August, 17 were present at one time at Paxton Pits; another 17 were on the Cam Washes and the Ouse Washes played host to over 25. Much greater excitement was generated by the arrival in Earith of a very rare vagrant to Britain: the Squacco heron. (A vagrant is a species which occurs accidentally within a region outside their actual range.) The squacco, despite its rather ugly-sounding name (seemingly derived from a local Italian word imitating the bird's harsh cry) is one of the most beautiful herons in Europe and had been at Earith, at the time of writing, from the 11th to the 13th August. The adult in breeding plumage is a lovely golden-ochre colour with a slightly purple-tinted mantle and elongated narrow dark-edged crown feathers, which form a sumptuous head-dress. The base of its bill is a greenish-blue. When it takes flight, however, it appears to be completely white because of its white tail and wings. It's a small bird compared with the grey heron (45cms/91cms) and usually skulks in reed beds but, as if to oblige the visiting 'twitchers', the Earith bird displayed on lily pads, giving good views. The squacco has only appeared in Britain and Ireland on a little over 100 occasions, usually when the birds, migrating out of Africa, have overshot their breeding grounds in southern Europe. Many of the recorded sightings occurred in the 19th century, after which there was a dropping off, probably due to the plume trade which also so badly affected little egret populations; recent declines in squacco numbers throughout Europe are probably due to the loss of wetland habitats so, with the Fenland Project under way perhaps we can look forward to more regular visits in the future!