A peacock butterfly female lays about 500 eggs under the top leaves of a healthy nettle plant. The eggs hatch out into caterpillars after about two weeks and the caterpillars immediately spin a protective web called a nest around the top of the plant.
This year’s butterfly count has been worryingly small so Ian Bushell’s discovery, yesterday, of two healthy peacock nests comes as a relief. Despite it being the third week of June, both nests look to be still in the early stages of development; the caterpillars will split up and go their separate ways in their final instars.
It is possible that the frosts at the beginning of May have delayed the development of some species of butterfly this year. For instance, the park’s first hatching of meadow browns was only a week ago and Lisa Burge’s sighting of the first large skipper the week before was also late this far south.
Perhaps these two peacock nests signify a turn of events and it will be a good year for butterflies in the park.
peacock nest 
final instar (CC0) 
peacock butterfly (CC0)
Photographs of peacock nests by Ian Bushell
More about the peacock butterfly:
PEACOCK CATERPILLARS
Yes there seem to be far fewer butterflies around than usual at this time of year. When I first received your email I thought you meant two nests of peacock birds. Probably not something you would welcome in the park.
No, peacock birds would be a real problem. I left the ambiguity in the title so that people would read the post. Sneaky.
Yes good idea, anything to get people’s interest is a good thing!