Dear Tweeters,

Howard Armstrong and I were up at the Hardy Burn last week, and noticed the usual large flock of finches at the sand piles. This location is along SR 20 in far eastern Skagit County, WA. We were wondering about this gravelling behaviour.

Finches present included, as usual, scores of Evening Grosbeaks, at least 14 Cassin's Finches, and quite a few Pine Siskins.

Since the Cassin's Finch is not, as far as we know, a very numerous bird in this area, we concluded that we were seeing the same fourteen birds over and over again, as they'd come and go. We were there for about three and a half hours. We couldn't get over how these birds kept returning to the same few spots, the same spots as they have visited over the last several years. There are other spots quite close by with similar-looking gravel and sand, but the birds don't usually go there. The presence of two dead deciduous trees, in which all manner of birds often perch here, might be part of the preference--there are watch-posts available.

We wondered, though, if they were indeed eating gravel, just how much gravel can a little finch eat, before it is overloaded? It would seem that only a few bills-full of sand would give a small bird quite a cargo to carry about. Or, were they mainly picking up salt? We were wondering if the gravel there might contain some de-icing substance, either rock salt or some other compound.

It does seem a bit extreme. These birds seem to be consuming more grit, and possibly salt, than food. Perhaps it's just because I usually visit there in the mid-morning. Maybe these birds forage at dawn, take a mineral break, and then gravel for a while?

Intriguing.

Yours truly,

Gary Bletsch ? Near Lyman, Washington (Skagit County), USA ? garybletsch at yahoo.com ? ?