Josef UyedaAlways struck by how much more the House Sparrow body size maps match the weather on the worst days of winter than it does the average climate of a region. 1) Today's temperature map 2) House sparrow body sizes 3) USDA planting zones
Just to make clear the implication: Natural selection on days like today is probably responsible for a massive proportion of the geographic variation in body size in House Sparrows vs. all the other factors that influence fitness throughout the year (inc. temp). If you live in the purple area, pour one out for the petite Passers that are dying outside (but don't feel that bad, they're invasive).
Stephen Cerruti@pseudacris oh good, for a second there I was afraid you were saying the size of house sparrows was causing colder temperatures and started researching how to use AI to eradicate sparrows in a certain size range but exclude juveniles.