First recorded

In a location that you monitor regularly (at least once a week), record the first time you see a live, active small white outdoors.

Overwinters as pupae and are first seen on the wing in March to early April.

There are two broods per year, observations made after the end of May are likely to be the offspring of the overwintering butterflies and should not be recorded.

Available historic data: we have very good data from 1891-1953 (6306 records), and good data from 1956-1999