A slow start to spring

Despite the tantalizing period of exceptionally early spring warmth, it has been something of a slow start to the season. There have been some early nests, with young Robins, Song Thrushes and Blackbirds evident in many gardens across the county, but other individuals were held up by the returning cold conditions. Now, however, it feels as if the pace is quickening.

We have seen a succession of arrivals, as returning summer migrants have been quick to settle on favoured breeding territories and deliver song. The Chiffchaffs were the first of these to be noticed here, around the brecks, followed by Woodlark, Blackcap, Willow Warbler and, most recently, Whitethroat. Early Reed and Sedge Warblers appeared late-month, with numbers of these reed- and sedge-bed songsters now increasing. The hirundines (swallows and martins) were slow to return in numbers and my first sightings of these summer visitors were behind those of recent years.

We have also had a smattering of passage migrants, in particular a good arrival of Ring Ouzels. These striking thrushes resemble a large Blackbird but with beautiful sculptured plumage markings and, in adult males, a white crescent around the throat. We have also seen some less common visitors in the shape of at least two Hoopoes, continental breeders that have overshot their breeding grounds off the back of southerly winds. They won’t linger, however, and will soon reorientate to return south. One of the most fascinating aspects of the unfolding migration has been the return of the Cuckoos, fitted with satellite tags by the BTO. Regular updates on their progress continue to appear on the BTO website (www.bto.org/cuckoos). The five tagged last summer, were all captured in East Anglia and it will be interesting to see if they return to the same sites.

The pattern of activity seen in our birds has been mirrored in the county’s butterflies, with a good number of early reports of species that overwinter in the adult form, followed by several lean weeks in which few sightings were forthcoming. Other species are now being reported on the wing, including Orange Tip and Holly Blue, so it does feel as if the butterfly season is now properly underway. Other insects have been taking advantage of early season nectar, with good numbers of bumblebees foraging in my garden and quite a number of hoverflies as well. The changeable weather that we see at this time of the year does deliver something of a stop-start feel and while it can appear that spring is here to stay one morning, the next can suggest a return to winter. It is a great time of the year to be out and about though as each new sighting delivers a thrill.

Ring Ouzels on passage

The last two weeks have seen very good numbers of ring ouzels at various sites along the North Norfolk coast. These birds, members of the thrush family, winter around the Mediterranean Basin and breed in upland areas across Britain and other parts of Europe. Given their preference for breeding sites situated on scree and boulder-strewn slopes, some 250m above sea level, it is hardly surprising that your only chances to see them within Norfolk come during their spring and autumn migrations. With their smoky black plumage, ring ouzels are superficially similar in appearance to a blackbird and, being of comparable size, there is the possibility of confusion between the two. However, adult male ring ouzels sport a large white crescent on their breast and have wing feathers edged with a greyish white. The crescent is absent in young birds, and less prominent in most females, but the feather edging should be sufficiently apparent to allow an accurate identification. To my eye, ring ouzels adopt a more upright posture, reminiscent of a fieldfare, than that seen in a blackbird.

Over the past two weeks we have seen a peak in the numbers of ring ouzels within the county, with small groups of birds dotted along the coast from Heacham and Holme to Winterton and beyond. These birds are likely to be en route to breeding grounds within Scandinavia; the British breeders having passed through the country several weeks earlier and arriving from a different direction. For these Scandinavian birds, the spring passage appears to be something of a leisurely affair, with individuals frequenting the same coastal scrub and dunes over several days. This provides them with an opportunity to feed and rest before migrating onwards to their final destination. In some years, males that have chosen to stopover here may indulge in a spot of singing, adding an unfamiliar song to the growing chorus of migrant songsters. The numbers of birds arriving during spring passage tend to be greater than seen during autumn and, in contrast to the pattern seen in autumn, there are also occasional records from well inland. Just last week, two were reported to me from near Diss. Although this pattern for inland records appears to have increased since the early 1990s, coastal sites are still favoured.

Like a number of other migrants, the ring ouzel population has been in decline and we have a seen a significant reduction in the size of the breeding range within Britain over recent decades. Although some of the causes of this decline may lay overseas, on the wintering grounds or migration routes, it is worth noting that acidification of breeding areas here may have reduced food availability and impacted upon breeding success.