Tuesday, 21 May 2019

Warblings

A fuller review of last weekend to follow but first I thought I'd just write a summary of how warblers have fared this spring. In short: it's been a bumper season.

Every spring I try to make an effort to count singing warblers as they arrive from Africa (come on, just how amazing is that). Although most warbler species are loud and distinctive singers there's a number of problems for me surveying them - weather and timing being the chief ones. With only a few survey days to play with if I visit too early in April or too late in May I would certainly miss some birds.

Numbers, therefore, vary from one year to the next and some of that is my surveying rather than population change. Having said that I've got a sense over the years of general trends. Timing and weather were good this year so what follows are likely higher than in a normal survey.

Note that I'm not claiming to count every singing male in the area - much habitat is out of reach. This is especially true of some prime warbler habitat - hedgerows/scrub, woods and wet areas. But, what I have is a fairly consistent effort to survey the same areas every year for 13 years!

Sedge Warbler - 20 males
This is the highest total in all the survey years. TA normal return would be 10-15, and the trend is fairly stable though they are confusingly up and down. Kelk Beck is the stronghold and accounts for 15 this year. Five elsewhere is a good score. Perhaps it really is a good year for them.

Reed Warbler - 2 males
There are three small reedbed sites where this species is regularly recorded, each typically hosting one or two males. This year two sites had one each and the third had none. Reed Warblers can arrive very late so it's possible this situation will be different in June.

Blackcap - 34 males
Another highest total in the survey years. As long as there's lots of cover Blackcaps are ok - gardens, big hedges, woodland. A typical year recently would see around 20 counted. There's been a few years where I haven't been very thorough in counting Blackcaps (as low as 12) but even so this appears genuinely to be a bumper year and the long-term trend has been upward.

Garden Warbler - 2 males
You never know where this species is going to appear - there are no guaranteed sites. I've never had more than three in a year so in that respect this year is typical. Woodland edge and tall scrub are the favoured habitats. Both this year's birds were in places I've never heard them before. The song can be tricky to differentiate from Blackcap and it's likely I've counted a few Gardens as Blackcaps over the years (must try harder).

Lesser Whitethroat - 11 males
Something of a mystery, this species. Their numbers appear to vary wildly from year to year and yet even the individual bushes they sing from are used again and again. A typical year would be 5-10 males, 14 in 2014 is the highest. Large bushes in hedgerows or scrub are by far the preferred habitat.

(Common) Whitethroat - 48 males
By some significant margin the largest count over the survey years. They were everywhere - and provided the main motivation for writing this piece. In 2018 a total of 28 was the largest count. A return of 20-25 would be normal. Long-term (discounting this spring) the trend is slighly upward. Whitethroats almost exclusively use hedgerows and perhaps farm stewardship practices have benefitted this species over recent years.

Chiffchaff - 32 males
Another highest total, eclipsing the 26 in 2017. April is the peak time for counting Chiffchaff. By mid-May they quieten down and there's no new arrivals to count. They are the most woodland of all our warblers local habitat though they will use more open scrub habitat like Blackcaps. There's no doubt this species has increased over the years.

Willow Warbler - 15 males
Recent years have seen 10-14 males counted so this is at the top end of normal. Last year's count of only 8 males was hopefully an anomaly - there was no particular lack of effort surveying. Woodland, scrub and large hedgerows are the favoured habitat but even in the best looking places they are thinly distributed. In the 1990s they outnumbered Chifchaffs but that's unthinkable now.

A couple of absences...

Cetti's Warbler - a male heard singing at the same site in both 2017 and 2018 raised hopes of expansion, in line with the situation across the region. So far this year, nothing doing. There's still time though!

Grasshopper Warbler - only recorded in two years recently, both at different sites near Kelk Beck. Clearly this is not a species one can expect every year so there's nothing much to read into it's absence.

A couple of photos...



Whitetroats were particularly active during this visit with several seen making song flights and singing from very prominent perches - something they don't readily do for much of the season.



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