Friday, October 8, 2021

2021Egg Lay

  Rejoice and be of good cheer! Despite a generally low adult emergence and a lot of grotty flight season weather, the Purple Emperor has managed to lay a goodly number of eggs, and larvae are in reasonable numbers this autumn. 

  I haven't quite finished my annual standardised count of autumn larvae in Savernake Forest, but it is already clear that 2021 will be the fifth best year in a 13 year sequence there.  Here's the data - 

2009 = 141        2014 =  24        2019 =  16

2010 =  59         2015 =  20        2020 =  12

2011 =  21         2016 =  17        2021 = E40* 

2012 = 22          2017 =  18

2013 = 190        2018 =  76

* E = estimate

Numbers seem relatively high elsewhere, though larvae are patchy. Also, tits are down - they had a rotten breeding season due to the cold April and wet May. 

All this suggests that 2022 could be a good Emperor year - only we need a cold winter, a non-early spring, and good weather during the pupal period (the worry here is that we are due a Platinum Jubilee in June, and the track record of weather during Royal Jubilees is  nothing short of appalling...).  

And larvae are running late. This year I found a 2nd instar larva at the start of October, in Glos, by far the latest record of the L2 stage. This is not a concern; they'll catch up, as sallow foliage is in good condition this autumn (though Sallow Mildew is prolific on overhung sallows).