23 eggs on a single sucker

A pleasant morning out egging in the sunshine today lead to a find of 23 eggs on a single small blackthorn sucker at College Wood in Lincolnshire. I am sure many fellow "eggers" will be familiar with this phenomenon - you search an area of apparently suitable habitat, maybe finding a few eggs here and there, then suddenly you find a tiny bit of blackthorn that has been favoured above all others by a mass egg-lay! This particular sucker was growing in a typical sunny, sheltered situation alongside a ride junction, and was about a metre in height. Of the 23 eggs, 12 were laid as "doublets" - ie 2 eggs side by side in the same fork.
Several questions spring to mind - were all 23 eggs laid by the same female (If so,  she has committed a significant percentage of her egg lay to just one plant)? What is it about this sucker that is particularly suitable for BH, if anything? Is it the location/aspect (there was plenty of similar growth in similar location with no eggs on)? Is there some kind of chemical messanger that attracts BH females to certain plants more strongly? Is it just a random phenomenon (I have doubts about that)? Are there occasions (eg after prolongued poor weather) when a female BH just has to lay many eggs in one go (my experience is that the females are rarely in any hurry to do anything at all - egg laying included!)

This afternoon I visited another of our "new" colonies. In 2010 I found eggs for the first time at Golsings Corner Wood reserve extension. This is an area of former farmland, acquired by the local wildlife trust a few years back, and planted up as woodland. It is situated to the south of an ancient woodland, from which blackthorn scrub is being allowed to develop. There is extensive blackthorn hedge surrounding the site, and blackthorn has also been planted within the new plantation. It has developed nicely into a great potential site for BH, and is close to our main stronghold at Chambers. I am delighted to report that I found eggs there today once again - the third year of confirmed occupancy!

Bring on the frost and wind - we need those remaining leaves to fall from the blackthorns!

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