Lisa asked about Nasal Disks on Barrows Goldeneye:

>From memory - nasal disks clip on a bit like a lapel badge ar a stud
fastener . They are "attached" using a plastic strip which passes through the
gap linking both nostrils - you can see through this BTW.

This technique for marking birds is not that common - it works really well
with waterfowl where the beaks are relatively large and have a flat surface,
so the disk doesn't impede the bird's vision. Not sure if there are any
documented ill effects - first reaction is I wouldn't think so.

Hope this helps - sorry for being vague.

Stuart
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Stuart MacKay, Ravenna Ave NE, Seattle