Data from: Selective bird predation on the peppered moth: the last experiment of Michael Majerus

Colour variation in the peppered moth Biston betularia was long accepted
to be under strong natural selection. Melanics were believed to be fitter
than pale morphs because of lower predation at daytime resting sites on
dark, sooty bark. Melanics became common during the industrial revolution,
but since 1970 there has been a rapid reversal, assumed to have been
caused by predators selecting against melanics resting on today's
less sooty bark. Recently, these classical explanations of melanism were
attacked, and there has been general scepticism about birds as selective
agents. Experiments and observations were accordingly carried out by
Michael Majerus to address perceived weaknesses of earlier work.
Unfortunately, he did not live to publish the results, which are analysed
and presented here by the authors. Majerus released 4864 moths in his
six-year experiment, the largest ever attempted for any similar study.
There was strong differential bird predation against melanic peppered
moths. Daily selection against melanics (s ≃ 0.1) was sufficient in
magnitude and direction to explain the recent rapid decline of melanism in
post-industrial Britain. These data provide the most direct evidence yet
to implicate camouflage and bird predation as the overriding explanation
for the rise and fall of melanism in moths.