Greetings,

With all the snow and consequent Pine Siskins, we have been noticing quite
a variation in plumage: from quite a bit of yellow to hardly any, from
pretty dark to pretty light stripes, overall darker or lighter plumage, and
even some quite noticeable variation in size.

Can anyone tell us, are these variations due to gender, age, subspecies,
other factors, in any particular way, or just in general?

Thanks for any info, or guesses,
Alan Richards / Naselle WA 98638 / USA