Red-winged Blackbird (Agelaius phoeniceus)
   
 
Narrative and Science Lens
 

Audubon shows the easily recognized red shoulder epaulets of black male in flight, which can be flashed as a signal or hidden, when dominant males are near by.

Brown-headed Cowbird females also recognize this species and frequently parasitize (that is, lay their eggs in) redwing nests.   The frequency may vary widely, but up to three quarters of Red-winged Blackbird nests may be parasitized. Why so many? Cowbird females lay a lot of eggs--up to 36 eggs annually--lay them earlier in morning than do the blackbirds, and lay them more quickly. The odd egg out in this photo is that of a Brown-headed Cowbird, laid in a red-wing nest.

Couresy Flugel get perm.
 Although these blackbirds protest aggressively, especially males, pairs will not eject the cowbird egg and will foster the nestling. Why aren’t the aggressive males more effective at deterring the female cowbirds?  Red-winged Blackbirds are polygynous (males have more than one mate), and in some populations need to defend the nest of more than one female.  They also need to defend against more than cowbird intruders:  Up to 50 percent of red-wing nestings carry no genes of the territorial male.
 
  Campus Locations
Common breeder in mustard and other herbaceous vegetation on the hills near the Dish and near Lagunita, fairly rare as a breeder elsewhere on campus. A few pairs may nest in the wetland area south of Campus Drive between Lomita Drive and Palm Drive. During the nonbreeding season, small numbers (and occasionally flocks) may forage throughout campus.
  Campus sustainability
 

       What you can do
  1. Report any sightings—especially if you see evidence of polygmous behavior (male red-wings frequenting more than one nest; or cowbirds in redwing nests
  2. Record activity--flying, perching, feeding, being mobbing (Stanford joggers as well as crows, ravens, and hawks).
 
  Science
       Essays from The Birder’s Handbook:
            Polygyny; Red-wing Coverable Badges; Visual Displays; Communal Roosting; Sexual Selection; Cowbirds
       References:
           Orians, 1980, 1985; Ewald and Rohwer, 1982; Yasakawa, 1979.
       Videos:
  Art
       Photos:
            T (g)
       Drawings and Paintings:
            DW drawing after Audubon
 
  To add reports or images please submit them via the Art at Exits home page