Common Introduced Non-Native Passerines and the Native Species They May Be Confused With

Red/Pink Mouths as Babies

Look at mouth color first. That will help rule out a lot of possibilities.

Important: There are other red-mouthed baby birds that are naked and don't have down, but are usually not confused with House Sparrows, including:

• California Scrub Jay and Steller's Jay

• Acorn Woodpecker

Baby House Finch (native) vs English House Sparrow (introduced)

• Easiest way to tell the difference between these two common birds

  • House Finches have fuzz!

  • House Sparrows don't!

  • I have yet to find a North American passerine with the combination of a smooth, gray-white chest with no markings/streaking, pale eyebrow stripe, and no striped crown that can be anything but a House Sparrow. (Please let me know if you find some other bird with this combination.)

Adult Females - House Finch (native) vs House Sparrow (introduced)

Brown-headed Cowbird (Invasive)

 Invasive bird species in California. Cowbirds are brood parasites. The mother bird lays her eggs in the nest of different species of birds which then raise the young cowbirds as their own. This is devastating to native bird populations. The female brown-headed cowbird usually takes the host eggs out of the nest and lays a few of her own in the host nest. This has led to two California birds beign placed on the endangered species list (Bell's vireo and willow flycatcher). It is not recommended to remove cowbird eggs from parasitized nests due to mafia behavior in which cowbirds retaliate by destroying the hosts' other eggs.

Source: https://wildlife.ca.gov/Conservation/Invasives/Species/Cowbird, https://goldengateaudubon.org/blog-posts/cowbirds/, https://www.pnas.org/doi/10.1073/pnas.0609710104, https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=86496

Yellow Mouths as Babies

Look at mouth color first. That will help rule out a lot of possibilities.

Baby Northern Mockingbird (native) vs European Starling (introduced)

• European starlings as nestlings have a very wide, very prominent gape flange, with the lower much wide than the upper.

Yellow-mouthed birds with prominent gape flanges that are NOT European starlings:

• http://www.pwconserve.org/wildlife/birds/bluebirdtrail/hatchling.pdf  (pictures of Eastern Bluebirds that are probably similar to Western Bluebirds that we have in California)

Adult Mockingbird (native) vs European Starling (introduced)

*indicates characteristics that help distinguish native from introduced species