Red Crossbills feeding on spruce seeds

  • Another creature that can live off Sitka spruce seeds is the Red Crossbill.
  • The male has a brick red body and the female is dull olive gray with a yellowish rump
  • Red Crossbills feed mostly on cones attached to the trees, though fallen cones may be important sources of seed.
  • This video shows them feeding on Sitka spruce cone seeds at a Red Squirrel cache.
  • Uses mandibles to bite between cone scales, so that lateral abduction of lower mandible (in the direction of its crossing) opens the cone scale, thereby exposing the seed.
  • Removes seed coat by using tongue to press seed against lateral groove opposite the side of the lower mandible tip; width of this husking groove influences husking efficiency.
  • Swallows small seeds whole, but crushes large seeds in bill before swallowing them, with some loss of pieces, though these may be reclaimed if they fall on branch where bird is foraging.
  • Red Crossbills generally eat up to 2,100 spruce seeds per day.
  • Of interest is these birds may nest almost any time of the year, even in Winter.
  • Why would a bird in Alaska nest in Winter?
  • If the cone crop is good and abundant then they would have enough food to survive and feed their young.

Red Crossbills feeding on spruce seeds from Bob Armstrong on Vimeo.

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