Crow City–How Smart are Corvids?

Corvids are a family of birds that include crows, ravens, jays, nutcrackers and magpies. You may note that in the movies ravens and crows are normally associated with evil. The evil witch or sorcerer such as in “The Lord of the Rings” or “Snow White and the Huntsman”. They are portrayed as surviving very well in apocalyptic movies. Those who work with Snowy Plovers here on the West Coast view them the same way. 100% of Mendocino County’s Snowy Plover chicks this year were depredated by the Common Raven. 

North American Birds online states:

Impacts On Prey Populations

Over a 10-yr period in California, ravens took 1.2% of 5,708 eggs of the endangered Least Tern (Avery et al. 1993). Ravens primarily take juvenile desert tortoises, a threatened species, with carapace length ranging in size from 32 to 105 mm ± 19.94 SD (mean = 67.1, n = 341, WIB); the level of predation may be sufficient to prevent recruitment in declining populations (Congdon et al. 1993). In Oregon, 14% (95/674) of Greater Sandhill Crane (Grus canadensis) nests were depre-dated by ravens from 1966 to 1981 (Littlefield 1986). In Arizona, 37% of 282 Pinyon Jay (Gymnorhinus cyanocephalus) nests were depredated by either ravens or American Crows (Marzluff 1988). Ravens preyed on breeding western toads at 3 of 15 breeding aggregations, eating >20% of the breeders at one aggregation in California (Olson 1989). Ravens and American Crows ate so many eggs at several Herring Gull (Larus argentatus) and Ring-billed Gull (L. delawarensis) colonies that they may have been responsible for complete failure of three colonies (Ewins 1991). Predation by ravens is thought to explain the high degree of nesting synchrony in Common Murres (Uria aalge; Murphy and Schauer 1996). In a Thick-billed Murre (U. lomvia) colony, ravens were responsible for <10% of the breeding failures (Gaston et al. 1985).

 

There is no doubt that corvids are some of the smartest animals on the planet. With climate change endangering our bird populations it appears that Corvids will do just fine. I came across this YouTube video on Grist and thought it was interesting.

“In an age of boom­ing cities, ris­ing tem­per­a­tures, and van­ish­ing wildlife, there’s at least one crit­ter that’s doing just fine: the hum­ble crow. But if it weren’t for us, they wouldn’t have it near­ly so good”

 

Please don’t encourage the growing populations of ravens and crows by feeding them. Keep your trash covered.

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One thought on “Crow City–How Smart are Corvids?

  1. Corvidea within WP « bearspawprint

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