Dennis Forsyth writes: I’m finding the interaction between the Siskins and Goldfinches at my feeder interesting. I suppose I should have expected this – the two species are fairly closely related – both in the Cardeulis genus – and they are quite similar in size. Most importantly, they both seem to be hyper-aggressive at this time of year. In any case, they are equal-opportunity battlers and apparently eager to engage in combat either with others of the same species or with anybody else who happens by. Below are two Goldfinches about to engage and a Siskin attacking a Goldfinch. In the inter-species fights they usually come to a draw and neither one appears to have a distinct advantage. Dennis
