[obol] Huge TRICOLORED Blackbird nesting colony

[Arch McCallum]

At 04:15 PM 5/20/2007, mike denny wrote:




>Mike's post about the large tricolored blackbird colony is really 
>interesting because of its similarity to the situation in Kern Co., 
>CA. Down there, the species has largely abandoned the marshes and 
>nests in wheat fields on huge industrial dairy farms. The blackbirds 
>find everything they need on these farms. The wheat provides the 
>kind of stems they need for nest placement. The feedlots provide the 
>adults with all the grain they can eat, and the alfalfa fields are 
>homes to the insects the birds feed their young. All these 
>essentials are within less than a mile of each other, cutting the 
>travel costs for a species accustomed to long flights from nesting 
>colonies in marshes to feeding sites.  The only thing wrong with 
>this heavenly setting is that the dairy farmers want to harvest 
>their wheat on time, when the young blackbirds are still in their 
>nests. This has led to large expenditures by wildlife agencies to 
>buy entire wheat crops from farmers that host tricolors. The 
>population in the central valley is declining.


Happily, the colony Mike described is nesting in wild rose, rather 
than in wheat fields. The alfalfa is probably the reason for the 
large size of the colony. Bully for northwestern Tricolors!

Arch McCallum
Eugene, OR