Friday, 15 June 2012

What's in the Box?

Had a busy day planned today checking nest boxes at Manor Farm and then doing some dormouse monitoring at Titchfield Haven, and so a 5:30 start was the order of the day.

There are eight owl boxes at Manor Farm, which are situated in a variety of locations, and many have been used over the last few years. We started down near the farm museum and were instantly rewarded with a brood of six Common Kestrels. The chicks were very well advanced and had almost fully grown wings, but we still managed to ring them.

Juvenile Kestrel

The weights of the different birds ranged from 189 to 210 grams so they were all healthy, the parents must have worked so hard to rear six chicks.

A Cosy Brood of Kestrels

The next box that we checked is located in the farmland in the middle of the park and last year there was evidence of a roosting Barn Owl but no sign of breeding. However during the early spring, when in search of Woodcocks, we had heard Barn Owls calling, so I was quietly hopeful that we would be in luck. Sure enough as I looked in the box there were two chicks nestled in the bottom. The larger chick weighed 380 grams and was beginning to grow its feathers but the smaller one weighed only 300 grams, but it did have a very full stomach. It must be so difficult for Barn Owls to provide enough food when we have weather as bad as we've been having in the UK recently. I will go back and check on them in a couple of weeks to see how they are doing.

Barn Owl Chicks

The next box we checked had been occupied by Grey Squirrels in previous years, but this year there was another brood of Kestrels. Well when I say a brood, one chick, one long dead chick and an addled egg. So a much smaller brood than in the other box, but success all the same! This chick was smaller than the smallest chick in the other brood, but only just, weighing 182 grams.

Juvenile Kestrel

The next two boxes were empty, but then success again, this time a brood of two Stock Doves. These birds were just starting to grow their primary feathers but one was still quite downy, and weight wise they were very similar at 238 and 242 grams. I have not ringed this species at the park before so it was a nice addition to the ringing list.

Stock Dove Chicks

The final box was also occupied by Stock Doves, but the eggs had not hatched yet. Before leaving we popped into the stables to check on the resident Barn Swallows. Five chicks were in the nest but they were too small to ring so we will have to go back next week. 

My next stop was a visit Titchfield Haven for some dormouse monitoring. I have been helping out with the monitoring for a couple of years now whilst also training the rangers towards a Natural England licence. We started at a site to the west of the main reserve where 30 boxes are up, and had several other rodent species, Yellow-necked and Wood Mouse and Bank Vole, before we found our first dormouse. The nest was classic, stripped bark on the inside with very fresh, green leaves around the outside, it was so clean and tidy we felt bad disturbing it .

Dormouse Nest
The animal inside was a female and she was a good size, weighing 18.5 grams, and seemed to be quite unperturbed by the handling experience.

Female Dormouse

In fact, she was so relaxed that she seemed to find it a struggle to stay awake.......bless!

Sleepy Female Dormouse

Our final stop was Titchfield Haven and the boxes around the bird ringing area. There is a mix of nest tubes and boxes here, but only around 20 in total. We found a couple of nests which had been made this year, but no animals other than another Bank Vole, a nest with young Bank Voles in and another Yellow-necked Mouse.

Thursday, 14 June 2012

Reed Buntings and Damselflies in South Oxfordshire

There was a break in the weather today which allowed me to get out and do some breeding bird surveys, so I headed up to a site in South Oxfordshire. This site is lovely and consists of a mainly flooded site which is dominated with Hard Rush Juncus inflexus, but has a mix of other species including Common Spike Rush Eleocharis palustris, Common Club Rush Schoenoplectus lacustris, Hop Sedge Carex pseudocyperus and patches of Greater Reedmace Typha latifolia.

Bird wise there are several wetland species breeding on the site including Sedge Warbler Acrocephalus schoenobaenus, Eurasian Reed Warbler A. scirpaceus and Water Rail Rallus aquaticus, but by far the most numerous is Reed Bunting Emberiza schoeniclus. There must be at least a dozen pairs nesting at the site, usually within the patches of Typha but occasionally in areas of less dense vegetation.

Reed Bunting Nest with Eggs
Typically Reed Bunting eggs are olive-brown in colour but these were very pale, however they still showed the usual black brown smudgy spots. Some pairs were feeding young and carrying a large beak full of grubs, but I didn't manage to find any of their nests. 

The sunny conditions were proving very popular with the resident chasers and damselflies also with Broad-bodied Chaser and Black-tailed Skimmer evident, whilst Common Blue Damselflies were the most abundant.

Common Blue Damselfly

Red-eyed Damselflies were present in smaller numbers and it was interesting to watch them vie with the more numerous Common Blues for the best basking spots.

Red-eyed Damselfly
As the Common Blues approached the Red-eyes would flick their wings to proclaim their territory, but this was often not sufficient and a brief aerial combat would be the outcome, with the red-eyed usually winning.

Saturday, 9 June 2012

A Ripe Old Age for a Blackbird

Another weekend and another missed opportunity for ringing due to strong winds and heavy rain showers....will it never end! 

Barn Swallows Hirundo rustica

So with no hope of mist netting I popped over to the local stables to check on the status of the resident Barn Swallows. There are 20 stables at this site and it was pleasing to see that most of the horses were out in the paddocks so I would be able to check the nests. The swallows were back and settled in, but not in as many numbers as last year, but still eight nests had eggs in, and another five looked to be active so I will have to pop back.

With the weather deteriorating I decided to do some data entry and whilst entering details from my last ringing session at Manor Farm Country Park, on 27th May, I noticed the age of a male Blackbird I had retrapped. This bird was originally ringed at Manor Farm on 16th November 2003, a distant 8 years 193 days previously, as a first year male. Although the age of this bird is not a national longevity record, which currently stands at 14 years 2 months and 1 day, it was by far the oldest retrap of any birds I have ringed. The bird wasn't in very good body condition and was well below the usual body weight, weighing only 80.8 grams (the usual range is 87 - 127 grams), which I presume is a result of working overtime feeding chicks rather than old age. Interestingly, it was only the third time it had been captured since its ringing date, so it would appear it doesn't frequent the farm museum very often, or else it remembers what a mist net looks like!

Tuesday, 5 June 2012

Birds and Bugs

A long weekend and the time to do some quality ringing was ruined by heavy rain, strong winds and Jubilee BBQ hangover. Nonetheless I did manage to get to Botley Wood on one occasion and was rewarded with a small but varied catch. My main target was once again Common Nightingale, but this species eluded me this time, although I did see three, and heard another three singing. The session was worth the effort and included several migrant species, one of which being my first Garden Warbler of the year. There were several birds singing, but the individual I caught was presumably a female since it had a well developed brood patch.

Garden Warbler

Both adult and juvenile Garden Warblers undergo a complete moult on their wintering grounds and therefore in the spring juvenile birds appear as fresh as adults.

Garden Warbler
This bird was extremely fresh, although there was some slight bleaching to the tips of the primaries, but the tips were not worn at all.

Wing of Garden Warbler

Similarly the tail feathers were very fresh, and surprisingly pointed, given that adult feathers are usually more rounded.

Tail of Garden Warbler

I also caught a couple of Common Whitethoats, one was a female, again with a very well developed brood patch, the other was a male. Common Whitethroat is a species where adults and juveniles undergo a partial moult on their wintering grounds, and therefore it is only possible to age birds by the extent of abrasion on the wing feathers.

Male Common Whitethroat

The primaries of the male bird (below) were very worn and faded at the tips, and the primary coverts were pointed. In addition the third, and largest, alula feather appeared to be of a different generation than the second, thereby indicating that this bird was a second year.

Wing of Male Common Whitethroat

The tail feathers were also worn and abraded, but they did show extensive white on the outer tail feather and on the tip of the second, a feature typical of an adult bird, in the autumn anyway.

Tail of Male Whitethroat

A Willow Warbler was the next interesting species to catch. Both adult and first year birds undergo a complete moult on their wintering grounds, and therefore there should be no discernible differences in their plumages in spring. However, Svensson states that some birds return in the spring with quite worn wing and tail feathers. This is attributed to one of three things;

1). a second year bird retaining juvenile flight feathers;

2). an adult which has inhibited its winter moult; or

3). a bird which has moulted very early in the winter. This is considered by Svensson to be the most likely. 

Worn Willow Warbler

As can be seen in the image below the tips of the primaries are extremely worn, not what would be expected from a bird that had moulted on its wintering grounds.

Abraded Wing of Willow Warbler

In addition the tail was extremely abraded, and interestingly there appeared to be two generations of feathers, with the central feathers showing what looked to be evidence of a fault bar, and therefore possibly retained juvenile feathers. 

Abraded Tail of Willow Warbler

Surprisingly this is now the third time I have captured a Willow Warbler in the spring at Botley Wood with extremely worm wing feathers. The first bird (below) had replaced a few secondaries, but all of the primaries and tertials, and the majority of the secondaries were old.

Another Spring Willow Warbler with abraded Wing

The wing of the other bird was so worn it was surprising this bird had made it back at all! In Svensson this is described as a rare occurance but given that I have encountered it three times since 1995, it presumably not that rare. Could it be evidence of an external factor on their wintering grounds that is preventing birds from moulting?

Another Spring Willow Warbler with abraded Wing

Other interesting species encountered during the session were a glow-worm Lampyris noctiluca larvae. Only three species of Glow-worm have been recorded in the British Isles, and this species is the commonest, but in decline itself.

Glow-worm Lampyris noctiluca larvae 

On returning home I found this male Oedemera nobilis beetle in the garden. This species is most commonly found in grassland habitats, the male have greatly enlarged hind femora, as can be seen in the image below.

Oedemera nobilis male

Sunday, 3 June 2012

Garden Ringing again....

At last!....after a busy work and social calendar I finally managed to get out and do some ringing, well put a net up in the garden anyway. It was a steady session that resulted in 13 birds  of six species being caught. Greenfinch was the commonest species which was nice to see, since this species has been absent from the garden in the last couple of years. A single Goldfinch and a couple of Blue Tits added to the tally, as did a rather aggressive Jay. I am always careful with this species and plan my approach as they always seem to draw blood....and this bugger was no exception.

Eurasian Jay

After what can only be described as a painful few moments extraction I felt was in control and so set about ageing it. Adults undergo a complete moult post breeding, whereas juveniles only a partial post juvenile moult, which means that it should be possible to see some contrast in the wing feathers. In the case of this bird the secondaries, tertials and wing coverts appeared to have been replaced; the secondaries and tertials were jet black and glossy and showed very little abrasion.

Eurasian Jay, a stunning bird

Whereas the primaries were dull, faded, abraded and pointed at the tip, a feature typical of a first year bird. In addition the tail feathers were not as broad as would be expected for an adult, with the 5th feather measuring only 20mm wide, when measured 40mm from the tip. The cross bars on the primary coverts, alula and outer greater coverts were more characteristic of an adult bird, but given that this part of he wing had all been moulted this was not unexpected. Therefore I aged this bird a 5, a bird that was definitely hatched in 2011.

Eurasian Jay Wing

The next bird out of the net was a Starling. Two pairs nest in the roof of my house, but I still don't  manage to catch that many. In starlings both adult and juvenile birds undergo a complete moult in the autumn, although in adult birds this is sometimes arrested....according to my trusty Svensson that is!

Female Starling

Sexing this bird was fairly straight forward since this bird had a pinkish base to the bill with a pale circle around the iris. This bird also had a well formed and engorged brood patch.

First Year Wing of Starling

Looking at the wing, it was more typical of a species with a partial post juvenile moult, since the primaries, secondaries, tertials, primary coverts and tail feathers were all juvenile feathers, along with some of the greater coverts. The tail feathers were also broad and rounded, which is typical of juvenile feathers in the autumn for this species.

Broad and rounded Tail of First Year Bird

The final bird out of the net was a juvenile Great Spotted Woodpecker, still wearing its red crown feathers. So it looks like the local pair have successfully reared another brood, unfortunately I think the Blue Tits in my nest box were used as a protein supplement for this family!!

Juvenile Great Spotted Woodpecker

After furling the net I sat down to enjoy a relaxing glass of wine and was immediately aware of movement around the flower pots......and there was the local hedgehog pottering around in search of slugs......always a welcome visitor to my vegetable patch!

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