Willow Tits
The Willow Tit is in serious decline as a breeding species in Britain. So much so it is Red Listed. Reasons for the decline are not clear and changes in land use, and in particular the management of broadleaved trees, may be a factor as could be the increasing competition for nest holes from other tit species.
Part of the difficulty in assessing the status of Willow Tit is that its identification is less than straightforward. Do we know how many birds there are and in Norfolk in particular?
Ashley Banwell decided to look at the problem here in the NarVOS area and a Willow Tit project began……..
Willow Tits in Swaffham Forest
Willow Tits have decreased dramatically in the past few decades across the whole of the UK - a decline of as much as 80% has been shown on Breeding Bird Surveys and the Common Bird Census. In Norfolk there were only two accepted records in 2010 (both birds trapped at Hempton) and just 5 birds seen in Norfolk in 2011.
Clearly something was wrong here, either a genuine decline or under-recording or misidentification of this difficult to identify species in the past. As I love an ornithological challenge I decided to find out for myself which it was.
The first important task was to find Willow Tits for myself so I could spend time with them and learn their calls and in which habitats to search for them. Luckily on 25th March 2012 I was able to find a singing bird which gave away many secrets of this species. My learning curve was very steep and I took great pleasure in learning many new facts about this species which I had previously taken only a little interest in. Even now as I write this in December 2012, I still find it difficult to identify some individuals on plumage alone, even after studying them closely this year. I never confirm any sightings of a bird until I have heard it call – ‘si-si dzee dzee’.
During the summer and autumn of 2012 I walked many a mile through forest rides listening for their distinctive calls. Once in a while I struck lucky, but large areas of suitable habitat were silent - even on follow up visits. I discovered 20 individuals in total and I am hoping further survey work in 2013 will uncover more pairs and a clearer picture, hopefully revealing the true status of this species. So far, all 20 individuals are within an area 8kms x 2.5kms.
With the pair that I was watching in the early breeding season a Coal Tit was observed taking over a freshly excavated Willow Tit hole. Fortunately they quickly made another nest hole about 50m away and were seen feeding young a few weeks later.
Both the Forestry Commission and The British Trust for Ornithology are backing this survey with great enthusiasm, allowing access to their forestry and supplying colour rings so individual birds can be monitored. Already several custom-made Willow Tit type nesting boxes have been erected and several feeders have been placed within known territories.
All records are shown below.
Site 1 - total of 4 birds
25 Mar: one heard singing and calling, seen well.
31 Mar: male heard singing.
1 Apr: one heard giving 'dzee' calls. I found a freshly excavated nest hole in the top of a low stump but a pair of Coal Tits were seen later using it.
6 Apr: heard and seen at dawn, 2nd male heard singing.
8 Apr: seen carrying nest material into the top of a stump, female took the material while the male was singing.
9 Apr: bird seen going into nest hole, 3 birds seen in total with another heard singing, female had a few white feathers on her crown.
11 Apr: one heard calling.
14 Apr: male singing.
15 Apr: male heard singing.
7 May: pair feeding young at nest site, calling and singing.
26 Aug: pair seen.
27 Aug: one bird seen, 340m away from yesterday’s sighting.
2 Sep: one seen and heard briefly.
14 Oct: one seen and heard.
Site 2 - total of 2 birds
19 Aug: first found, calling 'dzee' then 2 seen together feeding on Common Hemp Nettle.
26 Aug: good views of 2 still feeding on Common Hemp Nettle, in exactly the same spot.
27 Aug: one seen in same place.
Site 3 - total of 3 birds
9 Sep: first found, 3 birds were seen - all calling 'dzee'. This was in a young (ca 6 year old) pine plantation.
11 Sep: seen in broadleaf wood nearby, only 'dzee' calls.
26 Dec: seen and heard calling and also a snatch of song on this sunny morning.
Site 4 - total of 2 birds
16 Sep: first found. A single found in a flock of mixed tits near to a young pine plantation with suitable nesting stumps. I had felt sure Willow Tits would be here, eventually I heard a faint 'dzee' call and then it started to sing. A second bird, a rather featureless individual, was watched nearby.
Site 5 - total of 3 birds
16 Sep: first found. A male heard singing; I had heard a call just prior to this. A ‘dzee’ call was heard from a second bird as the male sang above me in a tall pine. A pair seen foraging low down near to a young pine plantation with lots of bushy understory.
28 Sep: probably 3 birds seen. Lots of 'dzee' calls as they fed low down on Common Hemp Nettle, also seen feeding in oaks.
29 Sep: 1 heard and seen.
14 Oct: 1 seen and another heard.
23 Dec: 1 seen.
Site 6 - total of 4 birds
29 Sep: first found: seen and heard, lots of 'dzee' calls.
1 Oct: 2 seen and heard.
14 Oct: 4 seen and heard, very vocal early morning.
4 Nov: 3 seen and heard.
9 Dec: 2 seen.
Site 7 -total of 1 bird
29 Sep: first found. Just a single bird seen and heard calling, with other tits.
Site 8 - total of 1 bird
29 Dec: first found. A very vocal calling bird seen well.
Ashley Banwell
*See below for latest updates to this project*
APRIL 2018 UPDATE
At as 31st December 2017 we have caught a total of 41 Willow Tits, 40 of them in the dry coniferous woodland of Swaffham Forest plus a single bird in an adjacent damp broadleaf habitat. Annual totals have been:
2013 9 adults in Swaffham Forest
2014 10 adults + 9 nestlings in Swaffham Forest
2015 7 adults in Swaffham Forest plus 1 in Broadleaf
2016 4 adults in Swaffham Forest
2107 none
2018 1 adult in Swaffham Forest
The first 37 birds were colour-ringed, but the ringed birds were difficult to locate and especially difficult with regard to identifying the colour-ring combinations in the field. We therefore changed our methodology and the remaining 4 birds were fitted with Passive Integrated Transponder (PIT) tags. These PIT tags are attached to a ring on the bird’s leg and operate in much the same manner as a microchip does in a family pet.
The theory is that if you position a data logger in the forest, typically at a feeder or a nest, the bird will ‘check itself in’ when it visits. The data can then be downloaded on to a computer and analysed thereafter.
We have however, had some difficulties with the technology in that the bird has to virtually touch the antennae (which is attached to the data logger) before it will register. We have ordered replacement antennae which we are promised will work much more effectively so this part of the project is expected to be ‘up and running’ again very soon.
Allan Hale