In my last blog I suggested that the weekend's weather forecast looked ideal for bringing in a few tired migrants from the continent. In particular, I raised the prospect that we might find a yellow-browed warbler or two. Although I was proved to be right in my predication, I'm not going to claim to be a soothsayer as this species is becoming an increasingly regular visitor every autumn.
Yellow-browed warblers breed in Siberia before undertaking a long autumn migration to SE Asia. Every autumn a few birds were either blown off course or accidentally flew in completely the wrong direction and arrived along the east coast of the UK. In recent years, however, as more and more of them arrive in the UK each autumn, and with several birds remaining in the southwest throughout the winter, it is increasingly obvious that these are pioneers, scoping out alternative wintering areas.
Such behaviour is not unusual. Many birdwatchers now see blackcaps on their feeders during the winter, yet your field guides may refer to blackcaps as summer migrants. Indeed, our breeding birds are summer migrants, spending the winter in Spain or Morocco. The birds using our gardens in winter have been shown, from sightings of ringed birds, to have bred in Austria or Germany and have chosen to migrate northwest to the UK rather than risk a hazardous crossing of the Alps and Mediterranean!
It was, therefore, not too much of a surprise when the Waveney Bird Club caught a yellow-browed warbler in their nets during Thursday's bird ringing demonstration. Ring fitted, measurements were taken, revealing that this tiny waif weighed just six grams. It never ceases to amaze me how such tiny birds can successfully complete migrations covering several thousand miles every autumn, and return again each spring! Once released, the bird flitted into the lower branches of a nearby oak tree to rest and regain its composure before climbing into the higher branches in search of insects.
Although this yellow-browed warbler wasn't seen on Friday, another was found in the Sluice Bushes on Saturday morning. Even more exciting was the discovery in the same patch of bushes of a Pallas's warbler. Closely related to the yellow-browed, Pallas's warblers are much scarcer visitors to the UK, and tend to arrive a bit later in the autumn. In fact, this proved to be earliest ever Suffolk record. They are superficially similar to yellow-browed, but Pallas's warblers have a yellow crown stripe, and more obvious black stripe through the eye, and more obvious second yellow wingbar and a bright lemon-yellow rump.
Pallas's warbler by Tom Williams
Unfortunately, following the torrential rain that hit much of East Anglia throughout Sunday, there have been no further sightings fo eithe rof these scarce warblers. However, today's sightings have included a firecrest and at least one chiffchaff in the North Bushes (two of the latter were in the Sluice Bushes yesterday) as well as a late lesser whitethroat. Two blackcaps (male and female) could be late summer migrants or newly arrived winter visitors.
While scarce visitors always tend to grab the headlines, they tend to accompany commoner migrants, and there is a definite increase in reports of both goldcrest and redwing this week, as well as several starlings arriving over the sea. I was also pleased to find a male brambling among a flock of 80+ goldfinches along the North Wall this afternoon, proving that it's worth spending time checking through flocks of familiar birds and not saying "they are just goldfinches".
At the opposite end of the size spectrum, another highlight of the last few days has been great white egret. Although much more regular than they used to be, this is still a new species for many visitors, and with up to four birds around the reedbed you have a good chance of spotting one in flight. Bitterns are seen every day (at least once, sometimes more frequently) and several little egrets are usually on the Scrape.
Island Mere has been a good place to wait for sightings of the great white egrets and bitterns, as well as the regular family of otters, but there's a lot more to see there at the moment too. The coot flock is noticeably larger than in recent years and often includes a female scaup, male pochard and two or three tufted ducks, There are also little and great crested grebes on the mere, as well as several marsh harriers, buzzards and a couple of late hobbies. Several swallows and house martins are still passing through, too
The weekend rain has seen water levels on the Scrape rise considerably, leading to most of the remaining waders continuing their migration south. However, avocet have increased again to 22, several snipe can be seen around the reserve, and a single knot remains on East Scrape. A very late common tern has been seen for the last two days, and one or two pintails are present among the flocks of wigeons, gadwalls, teals, mallards and shovelers.
There are still regular sightings of Dartford warblers, stonechats, linnets and meadow pipits in the dunes, while the first red-throated divers of the winter are being reported offshore. Other sightings offshore over the last few days have included velvet scoter, eider, long-tailed skua, grey seal and even a harbour porpoise, but you may need a bit of luck to spot most of these.
Finally, despite Sunday's monsoon-like weather, there are still good numbers of common darter and migrant hawker dragonflies on the wing and I've seen red admiral butterflies both yesterday and today. A little more typical in such wet weather is the increasing variety of fungi around the reserve, with the common bird's-nest fungus near the pond proving to be one of the most popular.
Does it follow that the yellow-browed warbler might not have flown from Siberia, his mum and dad might have taken to Finland say? As with those birds that are here when it was previously rare, is it possible these and other warblers moved their bases on too?
It is certainly likely that some come here from the small but growing population in Finland, but the numbers arriving int he UK suggest that many must travel from much further east. Many of the Siberian breeding birds have Finland as the western limit of their breeding range, with birds from there migrating east through Siberia then south into southern Asia. If they set off in completely the opposite direction then their initial route takes them west, to the UK, from where they may migrate south to Spain (where yellow-browed warblers are also becoming more frequent) or West Africa. While some probably come here form Finland, others will certainly be from as far east as the Urals, if not further east. Ringing returns show that even some of our commoner migrants, such as starlings and redwings, migrate similar distances.