The attached file shows the first capture dates on Landsort for a range of commonly caught spring migrants, using data from 1988-2016. This evaluation is part of a longer term review of the Observatories data and therefore needs to be viewed as a ‘draft’.
For example, some of the early dates for species like Robin, Blackbird etc might well be of birds that were not on active migration but were over-wintering on the island. More work is taking place to determine to what extent we can account for over-wintering birds in future analyses.
More meaningful than ‘first’ dates of course are the mean dates and on-going analysis is evaluating this and we hope to have more information later this year.
Historically, and in particular in the mid to late 90’s and again in the period 2008-12 there were years when little, if any, ringing took place in April. Future analysis will take account of such bias, but for now it is hoped you find the raw data of interest.
In some previous years the first Ängpiplärka, Stenskvätta, Lövångare, Göktyta and Rödstjart (Meadow Pipit, Wheatear, Willow Warbler, Wryneck and Redstart) had already been caught by todays date, so they should be arriving with us any day now.