For this week's latest installment in my species of the week series I have deviated away from the 70 species to spot checklist to turn the spotlight on the amazing variety of wading birds that are passing through Minsmere right now. I could have picked any of about 20 species of wader, but have chosen the green sandpiper simply because we sent this fabulous photograph of one by Paul Lloyd.
Green sandpipers breed in the forests of northern Europe (with one or two pairs nesting in northern Scotland), and spend the winter in sub-Saharan Africa, passing through the UK's wetlands every spring and autumn. Typically, autumn starts early in the bird world, with the first southbound green snadpipers and spotted redshanks having been seen in mid June. They will have been failed breeders, or females who had left the males in charge. Now that we're moving from July into August, the numbers and variety of passage waders are increasing by the day.
Waders can pose identification headaches at the best of times, but in summer they can in a variety of plumages from full breeding to full winter, with various in between stages of moult, and the first juveniles are beginning to return just to add to the confusion. Luckily, green sandpipers are less variable than most, and are distinguished by the clear dividing line between white underparts and dark upperparts, green legs and narrow white eyering. Typically, they have a few small white spots on the upperparts. When they fly, they show a large square white rum and barred tail, which is very characteristic.
There are several other sandpipers to spot on the Scrape too. The common sandpiper is sandier brown above and has a white "comma" in front of the folded wing. They also have a very distinctive flight shape and bob vigorously on landing. Wood sandpipers are often confused with green sandpipers but are more slender, paler and more speckled above with a less black-and-white impression. They are also scarcer migrants, but August is a good month to see them.
By far the commonest sandpiper at Minsmere is the dunlin. This is quite a variable species, and it's important to get to know dunlins well if you want to get to grips with wader ID. In breeding plumage they have lovely black bellies, but many are already losing this and acquiring their plainer winter plumage, as seen below (photo by Chris Gomersall, rspb-images.com)
Look carefully among the dunlins and you might spot a curlew sandpiper or two with their longer, more curved bill. Whatever the plumage, the white rump gives them away in a flying flock, but on the water they can be easy to miss. So too can the tiny little stint.
There are a variety of other passage waders to look out for too, including grey, ringed and little ringed plovers, knots, ruffs, whimbrels, curlews, greenshanks, common and spotted redshanks, turnstones and black-tailed godwits. With luck, a rarer species may drop in to the Scrape soon, too. Our avocet flock has increased considerably this week, with 212 counted this morning - many of these will be passage migrants from the near continent or elsewhere in the UK.
Most of our black-headed and Mediterranean gulls have already moved on, but at lest 20 little gulls remain and the evening roost of larger gulls often includes yellow-legged and Caspian gulls. One or two Arctic terns are continuing to be spotted most days alongside the common and Sandwich terns. Among the ducks, it's worth trying to spot a garganey or two - but with all ducks being in their summer moult plumage this can be tricky.
If the thought of identifying all of these tricky birds sounds daunting, don't worry. We usually have at least two volunteer guides out and about to help you - or try taking a picture for us to identify.
Elsewhere on the reserve, two white birds have stolen much of the attention so far this week. A huge great white egret flew past Island Mere a few times yesterday before settling on the island in the middle of the mere. The other was even more unusual - this stunning leucistic sand martin that was photographed by Steve Everett as it fed over the Scrape. Although appearing largely white, it is not an albino as is doesn't have red eyes. Instead it is leucistic - a natural pigmentation defect that means it is lacking melanin, so becomes very pale.
Of course, there are also lots of dragonflies and butterflies to spot around the reserve, as well as a hummingbird hawkmoth that has been seen around the visitor centre for the last few days.
Finally, tomorrow sees the launch of an exhibition of the winning photos from a student wildlife photography competition organised by A Focus on Nature and the National Union of Students. The nine winning pictures are on display in the visitor centre, so take time to look at them during you visit. They'll be on display throughout August.