I don’t often see the Red Crossbill and the Pine Siskin because each species wanders far. They eat seeds from the recent cones of mature coniferous forests. The crossbill will nest whenever it finds a rich crop. The siskin is a more regular nester in time, but variable in place. Each of these finches will occasionally flock with the other.
The Red Crossbill is a bird with an unusual crossed bill. The upper mandible might cross to either the right or left. It evolved this way to facilitate extracting the seeds of cones. The crossed tips act as levers, allowing the crossbill to pry the cone scales open. The slightly smaller Pine Siskin, while it likes the same seeds, lacks this bill refinement.
Many dozens of these two species were eating gravel at ground level yesterday. Gravel is consumed because birds lack teeth and the small stones help to break down the plant fibres and may supply some nutrients.
A female Red Crossbill (which has a yellowish colour) is eating gravel. The upper mandible of this bird crosses to the right, but some cross to the left. Note the outstretched tongue.
A Pine Siskin is on the ground similarly eating gravel.
The female crossbill is on the left and the male is on the right. The siskins are in front.
This is a small portion of the large flock of crossbills and siskins.
These species spend most of their time high in trees. It is to those heights they return.
