Thornhill, Ontario

Fun Facts About Grosbeaks

  • The male Rose-breasted Grosbeak shares incubation duties with the female and is known to even sing while sitting on the nest.
  • The Rose-breasted Grosbeak is beneficial to farmers, consuming many potato beetles and weed seeds.
  • The Rose-breasted Grosbeak will breed with the Black-headed Grosbeak in areas where their ranges overlap.
  • Rose-breasted Grosbeaks are known for singing on moonlit nights, sometimes all night, but never very loudly.
  • The nests of Rose-breasted Grosbeaks are commonly parasitized by the Brown-headed Cowbird, possibly due to the singing done by both the male and female as they construct the nest.
  • Rose-breasted GrosbeakRose-breasted Grosbeaks’ preferred feeder items are sunflower, safflower and peanuts
  • The nests of the Rose-breasted and Black-headed Grosbeaks are so thinly constructed that eggs often can be seen from below through the nest.
  • The males of both the Rose-breasted and Black-headed Grosbeak share equally in incubating eggs and feeding young, despite having a much showier plumage than their respective females.
  • The Black-headed and Rose-breasted Grosbeak have unusual diets for birds with such a big seed eating beak. Throughout most of the year, over half of their diet is made up of insects. Their huge beaks allows them to eat large grasshoppers, crickets and other insects that have tough exoskeletons.
  • By singing a "male" song, the female Black-headed Grosbeak can trick her mate into thinking a rival male is nearby, forcing him to stay closer to the nest.
  • Black-headed Grosbeaks eat insects, weed seeds and fruits. Sunflower seeds are their favorite feeder food.
  • Black-headed Grosbeaks are one of the few birds capable of eating toxic monarch butterflies. They discard the wings before eating the butterfly in an apparent attempt to reduce the amount of toxins they ingest.
  • The Black-headed Grosbeak, along with the Black-backed Oriole are the two primary avian predators of the over-winter populations of Monarch Butterflies found in Mexico. Combined they are responsible for more than 60% of Monarch mortality at many of the Mexican roosting sites.
  • These two species feed twice daily at the roosts in mixed flocks of five to at least 60 birds and annually consume several million Monarchs in the Mexican roosts.
  • At one 5.5 acre Monarch butterfly colony, Black-headed Grosbeaks, along with the Black-backed Orioles ate an average of 15,000 butterflies a day. It is estimated that over 2 million butterflies were consumed during the entire winter resulting in almost a 10 % reduction of the roost's entire population.
  • Evening Grosbeaks like to eat wild cherries, but unlike other birds, they only eat the pits. After removing the fleshy fruit, they crush the slippery seeds with special pads in their “gross beak.”
  • So favored are cherry pits that Evening Grosbeaks sometimes seek out the pits voided by American Robins.
  • Evening Grosbeaks can break open seeds that require up to 125 pounds of pressure to crush.
  • Black-headed Grosbeaks have been known to feed at oriole nectar feeders.
  • Other birds like to eat wild cherries, but only Evening Grosbeaks target the pits. The slippery seeds are held firmly with special pads on the “gross beak” and are simply crushed. So favored are cherry pits that Evening Grosbeaks sometimes seek out the pits voided by American Robins.
  • Evening Grosbeaks manipulate cherries in their beak to remove the outer skin and flesh, the remaining seed is then swallowed after it is cracked open with their beak.
  • Evening Grosbeaks can break open food items that require up to 125 pounds of force to fracture apart in testing devices.
  • As with many finches whose diet is primarily vegetarian, Evening Grosbeaks are attracted to natural salt and mineral sources.
  • The Evening Grosbeak is an irruptive migrant that makes irregular appearances at winter feeding stations throughout much of United States.
  • The Evening Grosbeak was not commonly found east of the Rocky Mountains before the 1850’s. Winter irruptions now occur in all of the 48 contiguous states. This expansion may be attributed to widespread planting of box elder trees in landscapes across the east. Its seeds persist on the tree throughout the winter and provided flocks with a reliable source of food.
  • The Evening Grosbeak was named in 1825 based on erroneous accounts that they became vocal and active only “at the approach of night.” This erroneous belief persisted for years, and the name is still a misnomer.
  • Evening Grosbeaks seem to delight in snipping off the twigs of Sugar Maple trees and sipping the sweet sap.