Sightings


Ashleworth Ham CES Visit 11, 2018

Ringing at Ashleworth Ham

Visit 11 on 21 August 2018

The conditions for catching birds were perfect, slightly overcast, and only a light breeze. The trouble is that, in order to catch birds, there need to be birds present. The complete absence of bird sound whilst putting up the nets, soon materialised into the second lowest catch of the year. Whilst not totally unexpected, it is always disappointing to have fears confirmed. The catch of 30 birds was well below the averages (48 for last five years, and 52 for the full twenty previous years). The hedgerows are full of fruit, and a few insects are around, but for the time being, the birds appear to have left the site, a feature that has been noted in previous years. Numbers pick up again in mid- to late September, and good catches are obtained in October.

Whitethroat topped the list with six birds caught, closely followed by Blackcap and Redstart with five of each species. All five Blackcaps were re-traps, of which two were adults in full annual moult. Two each of Redstart and Whitethroat were re-traps, one of the Whitethroats being an adult in annual moult.

The Redstarts were all juveniles at different stages of their post juvenile moult. Two were females fully moulted out, but still recognisable as juveniles by the orange fringes on the greater coverts, the other three were males, one obviously so as it was nearly through its moult, the other two were only just recognisable as males, as their moult had just reached their heads, and a few white feathers were just beginning to show through their protective sheaths. It is this opportunity to see these intimate details of a bird’s life cycle, that is one of the major appeals of ringing. For the scientists studying populations, the data from Ashleworth show that in this area, Redstarts have had a successful breeding season, with 22 of the 31 individuals handled this year being juveniles.

Chiffchaffs on the other hand appear not to have done so well locally.  Most years at this time, the sound we hear most frequently is the disyllabic call note of the young birds keeping contact with each other. This year there is little or no sound of them, and the catching figures reflect this, each visit yielding an average of just over one bird per visit, compared with last year when each visit yielded 8.4 birds per visit, and 5.8 birds per visit in 2016. It will be interesting to see if visit 12 (the final CES visit) does anything to change these statistics, but it is doubtful if it will.

Mervyn Greening


Ashleworth Ham CES Visit 10, 2018

Ringing at Hasfield Ham

by Mervyn Greening

Visit 10 on Tuesday 14 August 2018

The electric fence, to protect the netting area from cattle, was re-instated yesterday, and was still standing when operations started this morning. Weather-wise, the conditions could not have been better, slightly overcast and with the gentlest of breezes. Whilst the nets were being erected it was noted that there was virtually no bird sound. So, despite the perfect conditions, it was no surprise that catching was very slow.

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If it hadn’t been for the arrival of good numbers of migrating Swallows and House Martins, some of which descended low enough to be caught, the catch would have been well below the average of 57. As it was the catch, with the hirundines, was slightly above average at 63. Of the regular birds, Whitethroat was top of the list with nine caught, followed by Bullfinches with six.

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Of the 63 birds caught, only five were adults, four of which were in post-breeding moult, while one had completed its moult. All the hirundines were birds of the year which had completed their rapid, short, and incomplete post-juvenile moult, which will be finished when they reach their winter quarters. Young Swallows look like adults, but with much subdued colours, especially the throat which is rusty rather than red. House Martin juveniles on the other hand look quite different from the adults. Their plumage is more the colour of Sand Martins, as the blue tinge to the black feathers is not developed until post-juvenile plumage. When the birds are in the hand, and the rump (which is white) and the underparts are not readily visible, then the head alone could easily be mistaken for a Sand Martin.

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During the morning the cattle paid us a visit, and the effectiveness of a fully operational electric fence was demonstrated, when the herd tried to walk through the hedge where the nets are, only for the leading cows to touch the fence and jump back; this in turn caused confusion for the cows behind which ran off. Question now is, do the others learn from the ones in front? Or do they all have to touch the fence at some time to know what it does?

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One of the interesting things for me at this time of year is seeing young birds at different stages of post-juvenile (PJ) moult. A multi-brooded species like the Robin, can have young ranging from birds still completely in juvenile plumage, up to birds of the year that have completed their PJ moult and look exactly like adults. It’s also interesting to see the difference in the speed at which PJ moult happens. Long distance migrants like Swallows have a rapid and incomplete PJ moult; Chiffchaffs and Willow Warblers have a partial PJ moult of all their body feathers (but not flight feathers) which takes a few weeks; Wrens which have a similar strategy, stay in juvenile plumage a long time, then have a rapid moult; and Long-tailed Tits have a complete moult so are indistinguishable from adults by September.

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Not all birds are healthy, and sometimes individuals are caught which cannot be ringed. Bullfinches and Chaffinches sometimes have mite infestations that cause their legs to develop growths. Such was the case with one of the adult Bullfinches caught today. In this male bird, the infestation has made the legs and claws grow unevenly and bigger.

 


Colour variation in the Southern Hawker Dragonfly

Dragonflies and damselflies emerge from their larval skins in an immature state and necessarily spend some time away from  water, avoiding contact with others of their own kind while their wings and external skeleton harden and their adult colours gradually develop.  The immature males of many species pass through a distinct juvenile phase during which they resemble females until their true colours as adult males  become apparent.

The Southern Hawker (Aeshna cyanea) is a large dragonfly which is quite common in our area. It may be familiar even to urban dwellers as it will visit quite small garden ponds. The species is readily identified by the conspicuous pair of large oval spots on top of the thorax (behind the eyes) and by the bands of colour across the tail end of the abdomen (whereas similar species have paired spots there).  According to W.J. Lucas (British Dragonflies, London 1900):  “At first the ground-colour is rather light brown, and the spots are yellow.  The latter change through green to blue, while the former becomes darker. The pterostigma is at first yellow.” (The pterostigma is the spot close to the outer end of the leading edge of each wing.)  In females the colouration of the abdominal spots normally stabilises as yellowish-green (although a blue form occurs very rarely).  The typical appearance of a mature male can be seen in the photograph below.

A mature male Southern Hawker; The Mythe, 8 August 2007

Recently I noticed a hawker which looked almost ghostly as it flew above me in the shade of a tree.  When it settled I was able to photograph it  and the image below shows that it was clearly an immature male Southern Hawker.  However, rather than the greenish tint I would have expected to see in the abdominal spotting, this specimen was displaying a powder blue colour.  It would be interesting to know if I have captured a temporary phase in the development of this individual or whether it is destined to be an exceptionally blue adult when fully mature.

An immature male Southern Hawker; The Mythe 20 July 2018

 


Newt Larvae News

Newt larva, approx 3cm, in shallow water

The pond with the newt larvae mentioned in the post of 25 June has shrunk to a miserable puddle 2 foot across.

Shrunken pond

As the water level descended I have been watching the newt larvae becoming bigger, coming up vertically to gulp for air in the fashion of adult newts. These larger ones are no longer visible. However, there are still some very small ones with external gills and feeble little legs that I am certain would be incapable of terrestrial life.

Will they survive in the mud? I’ve seen no dead newts, but what about predators? A week ago there were many diving beetles in the pond. This morning I saw a mole pushing its way round the soft earth of the perimeter. It appeared briefly from the tunnel, its fur patched with wet black gloop, before scuttling back off along the new tunnels. Are these newt predators?

Diving beetles taking air


Hornet Moth time

Hornet Moths (Sesia apiformis) are emerging from poplars in Standish. They spend several years as larvae feeding on the wood and roots of the tree, emerging often by burrowing out at the base of the trunk, so you can see signs at any time of year by looking for the exit holes which are about the size of the thickness of a pencil.

Copulating pair with crayon for scale

Old exit holes in base of poplar trunk with crayon for scale

Habitat. Poplar trees in garden


Ashleworth Ham CES Visits 2, 3, 4, 2018

These three visits took place on 18th May, 28th May and 7th June. Visit 2 on the 18th was a quiet visit, with 31 birds caught which is exactly on the average for this visit. It is always a quiet visit, with the adult birds getting on with the business of breeding, territories have been sorted out, females are laying or sitting, so there is little movement. All the regular migrants were caught, and probably the most notable thing about the visit was the catching of six linnets, of which two were re-traps from previous years.

Visit three on 28th May was a day with ideal weather conditions, still and overcast, but despite this we recorded a well below average catch of 24 birds. It was notable in that no Redd Buntings or Willow Warblers were caught, and only one Whitethroat. All the Sedge Warblers caught were re-traps, so it looks as though there have been no new arrivals recently.

Visit four on the 7th June, was another good weather morning, with plenty of cloud and only a gentle breeze. The grass is now long, and it took only a few paces into the fields for us to be soaked.  The bird song by now is much reduced, but the bubbling calls of curlew, which are an ever-present feature of the early visits continued.  Male redstarts being an exception and singing well.

It is usually on visits three or four that the first juveniles are caught. With the Spring that we have had, it was no surprise not to catch any juveniles on visit three, but it was nice to find that there has been some successful breeding, as the first youngsters were caught on this visit. Four species of resident bird provided the newly fledged birds, in the form of Blue Tits, a Blackbird, Chaffinch and a Robin. Any time soon we should get some juvenile Song Thrushes, because we have had the best year ever for adult Song Thrushes with eight new birds ringed and a couple of re-traps. Unfortunately, the one Song Thrush nest found was predated before the young could be ringed and fledge. Two Carrion Crow nests along the reserve boundary have been successful with visible young in each of them.

As would be expected, all the female birds caught on the last two visits have had brood patches that indicate they are sitting on eggs.  A female Grasshopper Warbler was caught with an incubating brood patch, so they are here this year, trying to breed, despite the fact that we thought there weren’t any, as we have not heard a singing male on any visit.

Cuckoos have been very active around the site, with up to two males seen regularly, and a female heard on several occasions.

Botanically, the fields are in their prime, with lots of Yellow Iris providing splashes of colour, and the meadow sweet, the Oenanthe and the great Burnet all flowering now.


House Martins

House Martins have been here for many years and I’m pleased to say that there are even more this year, building nests in at least two of the eaves of neighbouring houses.  Stonehills, Tewkesbury, GL20 5FG.  Two terrible photos attached.  I’m afraid that I don’t have a proper camera and they move too fast!

 


Ashleworth Ham CES Visit – April 2018

After a delay caused by the spring flood, the first visits to set up the ringing site have been made. Access was only possible wearing waders, and on Friday afternoon, waders were necessary to get into some of the net lanes. Today however, the water had subsided sufficiently, to make waders only necessary to get across to the ringing site. Once there, wellingtons were sufficient.

The customary greeting from across the ham of a curlew calling was made, and throughout the morning bubbling calls were heard, and at one point three birds came into the reserve. With much flood water still around waterfowl were present in reasonable numbers, a flock of twelve mute swans were on the flooded fields, along with Canada geese, greylag geese, mallard, shelduck and a few teal. Three grey herons and two little egrets were patrolling the edges of the flood. A pair of lapwing, that were no doubt hoping to breed were displaying over the flooded front field.

The late spring, with cold weather, then a flood, has led to the summer migrants arriving late, and although a few were caught, numbers were low, and only a few birds were singing. Willow warblers were the most noticeable, and a chiff chaff was also singing. A couple of bursts of Sedge warbler song were heard, a single whitethroat and late in the morning after it had warmed up two lesser whitethroats became very vocal. All around the reserve Skylarks were singing strongly, and a blackbird sang briefly. A few reed buntings were caught, but none were in breeding condition, and none were heard singing. One of the willow warblers caught had a ring on, that was not from Ashleworth, so where it came from will be reported later.

On the way out, at the end of the session, the remains of an otter’s dinner were found on the sluice gate bridge, along with lots of footprints and a fresh spraint alongside some old spraints. The bream and a carp had been brought to the bridge to eat, presumably caught in the flood water as it dropped. A number of large carp had been observed Friday afternoon swimming in the flood water, and presumably become easy prey as the water drops. Elsewhere across the ham a large flock of gulls could be seen, also feeding from the spoils of the flood. Back at the car in “dirty lane” two roe deer were observed for a while grazing in one of the new fields.

Birds trapped: Blackbird 1, Blue tit 3, Reed Bunting 3, Sedge warbler 2, Willow Warbler 2, Blackcap 1, Bullfinch 1, Chaffinch 1.

Birds seen: Mute Swan 12, Canada Goose 9, Greylag Goose 2, Grey heron 3, Mallard 16, Teal 4, Coot 5, Moorhen 1, Little egret 2, Skylark, Blue tit, Great tit, Blackbird, Song thrush, Robin, Dunnock, Wren, Sedge Warbler, Chiff Chaff 1, Willow Warbler 2, Whitethroat 1, Lesser Whitethroat 2, Reed Bunting, Linnet, Chaffinch, Bullfinch, Carrion Crow, Lesser Black Backed Gull, Kestrel, Buzzard, Curlew 3, Lapwing 2 , Oystercatcher 2, Woodpigeon.