[birding] bird identification help

[Carl & Christine Schneiders]

On a bike ride today I saw a flock of 300 (approx.) birds.  They were in an old cauliflower field, it was mud, grass, and old cauliflower stalks.  As I biked by I spooked them out of the field. (There was also a flock of killdeer in the field.)  They were about sparrow size, had average to long tails, were dark (I didn't get many details because they were back lit against the sky), and their wings were about average length and somewhat pointed.  Their flight pattern and flock habit was very different from any other bird I am familiar with.   They had a undulating flight pattern but not as distinct as a goldfinch.  They stayed together as a flock while flying but with some birds drifting out to the edge and then back to the center.  The whole flock circled the field a couple of times and then landed further away in the same field but I couldn't see them.  Their call was distinct it was a high pitched, slightly buzzy whistled two note call.  They weren't blackbirds, starlings, shorebirds, or meadowlarks.  I don't think they were sparrow because they didn't have a sparrow type call.

I thought they might be Horned Larks, so when I got home listened to their call and it sounded similar.  I tried to find pictures of Horned Lark flock but couldn't find any.  Are these bird identifiable to a species?  I'd appreciate any help.

Thanks in advance,
Matthew Schneider
Silverton, OR 
cncschneider at msn.com
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