Just like bluebirds, Blue Jays have no blue pigments in their feathers. Instead, each feather barb has a thin layer of cells that absorb all wavelengths of color except blue. Only the blue wavelength is reflected and scattered, resulting in their blue appearance to our eyes.
Blue Jays are often chastised for their known practice of eating eggs and nestlings of other birds. But extensive research has proven this to be a very rare occurrence, with only 1% of the study population showing any evidence of this behavior.
Blue Jays are known to migrate, but the phenomenon is not well understood by scientists. Research has shown that some individuals will migrate south during some years and choose to stay in the north during others. Why they do this is still one of nature’s mysteries.
It is estimated that only about 20% of the population of Blue Jays migrate, even in the northern parts of its range.
Peanuts in the shell are a favorite among Blue Jays. Watch your feeder to see if you can observe them shaking peanuts to tell if the shell is full or empty.
Blue Jays eating acorns alone quickly start to lose body mass, unless those nuts are full of protein-rich weevils or supplemented with other sources of insect protein.
Blue Jays mainly select undamaged nuts to bury; research has shown that only 10% of the acorns they cache are not viable seeds.
Blue Jays will bury seeds up to 2.5 miles from their original source, which is a record for any bird. This behavior has greatly helped with the range expansion of many oak species.
The rapid northward dispersal of oaks after the ice age may have resulted from the northern transport of acorns by Jays.
Due to Jay’s habit of burying acorns over a wide area, 11 species of oak trees have become dependant on Jays for the dispersal of their acorns.
Due to Steller’s Jay’s habitat of burying pine nuts, several species of pine trees have become partially dependant on them for the dispersal of their seeds.
Research studies have recorded Blue Jays making over 1,000 trips per day when hiding food.
In one research study, 50 Blue Jays were observed selecting and caching 150,000 acorns over a period of 28 days. Each bird cached a total of 3,000 acorns by selecting and hiding an average of 107 acorns per day.
A Blue Jay was observed packing over 100 sunflower seeds into it’s gullet during just one visit to a feeder.
The Blue Jay is a talented mimic; its version of a Red-shoulder hawk’s call can fool even the most experienced birder.