The first calm and sunny day of 2020 drew me to SML like a moth to a flame. After two weeks of dull, wet and windy weather confining me to home, I was starting to get cabin fever and, although bright conditions make the nets more visible and can reduce catches, knowing that the forecast for the next week is grim saw me slopping through the mud at 8am. In the not too distant past decent numbers of Reed Buntings roosted in the reedbed in winter and up to nine birds could be found together in the same net. However, these have declined significantly in recent years and, apart from the odd Cetti’s Warbler, the reedbed nets are not very productive in mid-winter. Consequently, I decided to try Crest ride at the wooded, eastern end of the reserve as an alternative, which provided a quarter of the birds trapped.
Catches in previous Januarys have ranged between 12 and 73 birds, depending partially on weather conditions and the number of visits, but principally on the presence or absence of chironomid midge swarms. Midges were few and far between today and the number of birds trapped reflected this with a final total of 28 of which just 14 were new. Five of the re-traps were Firecrests, a bird which manages to brighten even the dullest of days. Birds processed: 3 Blue Tit, 1 Bullfinch, 8 Chiffchaff, 1 Dunnock, 5 Firecrest, 4 Goldcrest, 2 Great Tit, 1 Robin, 1 Song Thrush and 2 Wren.
Given the continuing overcast weather, combined with other commitments over the festive period, I decided to make a start on revising some of the other pages on this blog. I’ve been working on a paper detailing the population dynamics of Chiffchaffs wintering at South Milton Ley. British Birds sent the first draft out to five reviewers and it returned with a lot of comments. Fortunately, these were almost entirely constructive and I have recently resubmitted a significantly revised second draft. When (or if) this is eventually published, I intent to expand the section on wintering Chiffchaffs in the blog considerably. However, in the meantime I have updated and sorted all the photos of Siberian Chiffchaffs ringed at SML since December 2014 into a thumbnail gallery, which can be accessed here:
Firstly, a happy and productive New Year to my handful of regular readers. My last day’s ringing at SML for 2019 turned out to be the least productive session ever with just one new bird and six re-traps caught in four hours with 90 metres of net erected. A minor consolation came in the form of a UK control Chiffchaff but everything was hard work. The weather was particularly gloomy with enough moisture in the air to condense on the nets requiring more frequent rounds than usual. The wind, although light, was from the southwest, the least favourable direction for trapping around the sewage works in winter and the ground was saturated making progress between and along the net rides slow and hazardous. Even my lightweight Daihatsu 4×4 with the diff-lock on struggled to find enough grip to get me and the ringing gear on-site.
I tend not to visit on days like this as experience has shown that most Chiffs are present when it’s calm and sunny, which encourages chironomid midges to swarm around the sewage works. It does make me wonder where the birds go when the weather is less favourable. Perhaps they feed in woodland and large private gardens further up the valley on days like this. Ringing in previous winters has shown the minimum population at SML to be around 90 birds with estimates, made using capture/recapture models, suggesting that the true figure could lie between 188 and 227. That’s a lot of disappearing birds!
Crops of photos taken recently at South Milton Ley by Richie Moore, published on the Devon Birds’ website and reproduced here, clearly show the importance of chironomid swarms to wintering insectivores when the sun is out. Reassuringly, all the birds have rings on!
A forecast for a brief period of benign weather and a much-improved back injury encouraged me to visit SML today. I had gone principally to work on the bridge to Marsh Ride as the water levels in South Milton Stream have overtopped the bridge a couple of times this winter, flipping it and moving it a few metres downstream. The resistance to the flow, caused by the boards, had also forced water up onto the banks at either end, softening them and causing the bridge to slowly sink. If left unresolved the whole lot could have been washed away or fallen into the stream during the next heavy downpour.
I had been racking my brain for an easy solution and came up with the idea of cutting and reconfiguring the steel bases from an old sofa and armchair we have just replaced to make support structures for both banks. These were hammered into a depth of c.50cm leaving the boards 20cm clear of the surface and any future overtopping of the stream. All at no cost as the metal was destined for the recycling centre!
The boards are like a skating rink as the chicken wire had collected a load of floating vegetation and eventually partially ripped off leaving a slippery wooden surface. Replacement wire mesh is on order! Despite not being finished, it already feels more stable and secure than I can remember. As a bonus, I have used the two, heavy, original boards together with two beams salvaged from the boardwalk bridge to extend the walking boards along the whole length of the net ride for the first time.
In between periods of construction, I had six nets (90 metres) up. Those beside the sewage works were particularly productive. These can only be erected on its SW perimeter and, in winter, the prevailing wind frequently concentrates insects and birds on the opposite, leeward side of the site, often resulting in frustratingly low rates of capture and recapture. The numbers trapped increase on calm days or when the wind has a northerly or easterly direction. Today, both of these criteria were met resulting in 58 birds being processed: 1 Blackbird, 8 Blue Tit, 28 Chiffchaff, 3 Dunnock, 4 Firecrest, 4 Goldcrest, 1 Great Tit, 1 Long-tailed Tit, 1 Reed Bunting, 1 Robin and 6 Wren.
A second back injury in 10 months has kept me virtually confined to the house for the last couple of weeks. All very frustrating as a couple of perfect ringing days passed by and other birders phoned up to tell me the Ley was “awash with Chiffchaffs” with possible sightings of Yellow-browed Warbler and Siberian Chiffchaff as well. With today looking like the only opportunity to ring for the next week, I bit the bullet and made my way to South Milton. In the event, I only erected the three nets closest to the ringing station as every step to the reed bed rides sent a jolt up my spine and the recent high water levels have stripped away some of the chicken wire on the bridge rendering the boards extremely slippery.
Consequently, numbers ringed were lower than usual with 30 birds processed: 1 Blackbird, 5 Blue Tit, 1 Bullfinch, 14 Chiffchaff, 4 Firecrest, 3 Goldcrest, 1 Redwing and 1 Wren. The Redwing was the first of the winter and was lured into a net using a tape known in ringing circles as “The Latvian love song”, which seems to have some sort of fatal attraction for the species.
Finally, a day with half-decent weather and no other commitments saw
me making an early journey to South Milton. Although a little windier than I
would have liked (F4/5 SE), an easterly element
had proved quite productive in the past so I was optimistic.
reserve is very wet with water levels in the upper reaches as high as I can
remember. The bridge across to Marsh Ride required further remedial work as the
wire mesh had collected a load of vegetation being swept down the ditch
and the whole lot had been moved a few metres downstream. I even found a Grey
Wagtail nest box, which had been attached to the bridge on the public footpath,
200m upstream, beached in Marsh Ride so it looks as though water levels must
have reached the base of the bridge some 2 metres above normal!
The ringing was steady throughout the day with 67 birds processed: 6
Blackbird, 11 Blue Tit, 1 Cetti’s Warbler, 21 Chiffchaff, 1 Dunnock, 9
Firecrest, 12 Goldcrest, 1 Great Tit, 1 Long-tailed Tit, 1 Reed Bunting, 1
Robin and 2 Wren. The Firecrest total is a new day record, beating the previous
figure of 6 during a big influx in October 2017 and three of the Chiffchaffs
were returning wintering birds, one of which was back for its third successive year.
I’ve had to snatch whatever opportunities the weather has presented
recently, looking for gaps in a seemingly endless succession of days which have
been either too wet or too windy. On both dates above the nets had to be closed
regularly as showers rattled through, which limited the number of birds caught.
Water levels in the Ley are very high at the moment and South Milton Stream has
risen until it is level with the bridge to marsh ride. It was quite
disconcerting, knowing that the ditch is now over 2m deep as the boards actually
dipped underwater when I walked across them.
Over the two days 86 birds were processed: 2 Blackbird, 12 Blue Tit, 1
Bullfinch, 6 Cetti’s Warbler, 16 Chiffchaff, 3 Firecrest, 11 Goldcrest, 4 Great
Tit, 1 Great Spotted Woodpecker, 10 Long-tailed Tit, 5 Meadow Pipit, 5 Reed
Bunting, 3 Robin and 7 Wren.
With only one rain free day in Plymouth out of the last 25 and blasting westerly winds as well it was a relief to see a half decent forecast for today. There were still a couple of light showers to contend with but it was pleasantly warm when the sun was out. If anything the weather was almost too good, allowing the Chiffchaffs present to feed in the tops of the trees and pass over the mist nets. I needn’t have worried though as they descended when it gradually clouded over. 41 birds were trapped: 3 Blue Tit, 11 Chiffchaff, 1 Dunnock, 1 Firecrest, 3 Goldcrest, 2 Great Tit, 5 Long-tailed Tit, 2 Meadow Pipit, 3 Robin, 1 Song Thrush and 8 Wren.
After spending two wind-blown and wet weeks at Portland Bird Observatory, with more ringers than birds on those few days when the wind dropped, I was keen to get back to South Milton. In reality the wind today was borderline but the forecast for the rest of the week is even worse so I took a chance. If all the leaves I caught had been birds I would have been kept pretty busy but ended the morning with just 11 new birds: 3 Blackcap, 1 Cetti’s Warbler, 1 Chiffchaff, 3 Goldcrest, 1 Meadow Pipit, 1 Robin and 1 Wren.
Unlike Nanjizal, where a record 618 birds were ringed yesterday, I struggled to get past 40 at SML today. So much so that I even found the time to photograph one of the last few Common Darters lingering around the site. The final total was 44 new birds: 22 Blackcap, 1 Blue Tit, 12 Chiffchaff, 2 Goldcrest, 3 Meadow Pipit, 3 Reed Warbler, 1 Wren