Blame global warning if you want

[Jane Turner]

I just altered the way store my bird records so now I can look at totals summed by quarter months. I intuitively thought this was the case, but now my data show that Willow Warblers are arriving earlier. It also shows that in recent years Spring records are predominating and that there is a distinct double peak observable - I assume relating to firstly British breeding birds then later Scandinavian ones.

The upper graph is pre 1985 and the lower on is post 1985...

Whatever the cause, the effect is observable!

[Michael Frankis]

Interesting.

I'd have thought the double spring peak is males and females - I doubt that many Scandinavian WWbls pass through western Britain, they'll mostly go up through Holland, Germany, Denmark to avoid the long North Sea crossing. They only appear on the east coast in 'fall' conditions, east winds and rain.

Michael

[Jane Turner]

From wing lengths of the trapped birds there is a second peak of males in May... and a dribble of acredula types. Ring Ouzel shows a similar pattern - though with much smaller numbers. Not got enough ringing recoveries to prove anything ... though two of the later birds made it to the northern isles..

Oh and we only get WW in late mid to may in drift conditions...the figures being skewed probably my me making every effort to be out there in drift conditions :)

[Adey Baker]

On my three local patches, although there are good numbers of Chiffchaffs, I've only had about 4 Willow Warblers, 3 or 4 Blackcaps and 2 (poss. the same one twice) Swallows so far this year - I blame 'Global Cooling!' :h?:

[Alastair Rae]

I'm not a statistics buff but I think you could interpret your charts differently. Haven't you lost the bulk of your earliest arrivals so you could say they're getting later?

[Jane Turner]

The part that most interested me was the absence of any records at all in the first q of April pre 1985 and there presence of a lot post 85. There is a fall of 270 on one late Apr day in 1998 which distorts the figures a bit.