Thanks to volunteer Phil for his report and photos!
Recent Sightings Weds 17th and Friday 19th January
On Wednesday I joined a large group of volunteers and staff on the annual brown hairstreak egg hunt. This is a vital activity for reserve management to provide information on where these very scarce butterflies are laying their eggs so that hedgerow management can be undertaken in the most effective way.
Brown hairstreaks are very fussy about where they lay their eggs, being almost exclusively on blackthorn bushes, particularly new growth such as suckers growing away from more mature bushes and most often in the corners where new thorns or side shoots are emerging from older stems. They prefer to lay on the warmer sides of bushes, more east and south than west or east, and generally roughly between knee and chest height. As with all wildlife however they don’t always read our script and we did find some exceptions.
The eggs can be seen relatively easily in winter time with a little initial help and practice. They appear as tiny white dots against the dark stems and are rather perversely easier to see when in shadow or on a cloudy day. They can be mistaken for other things such as tiny pieces of lichen, so it helps to use a magnifying glass to observe a round slightly domed shape. They can also be mistaken for eggs of the blue bordered carpet moth which can be found in the same sort of place but have a more oval shape.
When viewed under significant magnification, as in this macro photo of 2 eggs near the top of the Zigzag Path, they are revealed as marvels of natural design.
It is hard to imagine how something as small as a pinhead could show such intricate detail.
The hunt was conducted by 4 teams searching in different parts of the reserve and produced a record number of finds – over 100. As well as the Zigzag path eggs were found near West Mead, various places near the old path to Redstart Corner, behind Winpenny Hide and along Adder Alley, in front of the Hanger, by the path going to Nettley’s Hide and up the bank to the right of the path towards the cattle pens. Bushes where eggs were found were marked with small pieces of string so they can be re-examined, and a few visitors have noticed them already.
The importance of hedgerow management for butterflies, small birds and mammals, and other insects cannot be overstated. They can provide vital corridors to allow wildlife to link up with other areas of the countryside. A programme of hedgerow work has already started on the reserve, with some early evidence being readily visible from the Visitor Centre around the edges of Upperton’s Field. More detail is given in a recent post on our blog under the title of “Hedgerow Heroes”.
My egg hunt team surveyed the area from Winpenny to the Hanger and spent some time towards the end wandering around the slopes in front of the viewpoint, doubtless causing much puzzlement to the visitors standing there expecting to see our Temminck’s stint. I was too busy to worry about the birds, but was struck by a completely different low-down perspective on the magnificent large willow tree in prominent view from the Hanger and sometimes known as the Peregrine Tree because of the past fondness of some peregrines for using a particular branch as a lookout post.
The tree is often occupied by various birds but this winter the peregrines, despite being on the reserve regularly, don’t seem to have been using it.
I have mentioned black tailed godwits in several recent posts. A colleague of mine once remarked that if you see one probing for food into mud or soft ground the long bill looks rather like a sewing machine needle moving up and down at speed.
Black tailed godwit numbers have increased enormously within the last week. On my last Friday visit I had estimated about 100. Various reports since then have recorded large jumps in that number, almost on a daily basis, and on Friday estimates had risen to around 800. My pre-Christmas speculation about a bumper New Year for this species seems to have hit the mark. However, I think the reasons I gave about the higher water levels may have only been a part of the story because, as reported last week there was a big drop in the level after the New Year. My guess now is that the deeper and more extensive water area present for several days had the effect of softening the ground more to give better feeding opportunities.
Seeing all these birds is a magnificent sight, especially when they fly. The grey winter plumage suddenly reveals a brilliant white underside to the wings when they wheel away from the sun. I couldn’t quite catch this on Friday but here is a breakaway group flying off purposefully to feed on the South Brooks.
The next photo shows a large cloud of godwits over the North Brooks having been disturbed by a peregrine.
When returning to rest the birds seemed to have a liking for settling into a long line, ideally positioned for counting.
Here is a close up of a small section of the line
Scanning along the line revealed an interloper in the shape of a solitary avocet, an unusual sighting here as this species is usually coastal especially in winter.
Along with the ubiquitous lapwings, small numbers of dunlin and ruff, plus solitary green sandpiper, golden plover and Temminck’s stint, completed the set of waders seen on Friday.
Hawfinches are still being seen regularly in the same places (Zigzag Path, the trees towards Wiggonholt Church, and the bushes by the Hanger), and all our usual winter wildfowl is still here in large numbers being harried by peregrines and other raptors.
There has been a report within the last week of “bean geese” on our sightings page in the Visitor Centre. Last winter from late January a group of 5 tundra bean geese spent a few weeks on the reserve so it may repay taking a closer look at all the geese to see if something more unusual is mixed in. Tundra and taiga bean geese are very scarce winter visitors to the UK and are members of a group of species sometimes loosely referred to as “grey geese” so they are more similar to greylags than Canada geese.
Also worth looking out for is a great white egret as one has been seen in the Arun valley recently.
Leaving the Visitor Centre at the end of Friday I was struck by a beautiful new moon hanging over the trees and it seemed like a symbol of hope for another exciting year at Pulborough Brooks.