ML614363576

観察結果の詳細

Likely Rusty, but not totally sure. First seen by Alice a bit earlier and ID'd as Rusty/Brewer's. I got to the feeder just in time to see it get taken out by a SSHA. Cellphone pictures of it alive from earlier. Hawk took it into the bushes and after waiting a while to let it eat I went to look for the carcass. Hawk was still on it and took off with it but left the bill. Reasons for not defaulting to Rusty (although it probably is): Cellphone pictures not great for details, but plumage most similar to 'drab adult male non-breeding' Brewer's in the Sibley's and 'immature male' Brewer's in Nat Geo guides. Main feature is the uniformly dark (pretty well black) wings with no visible edging combined with a faint lighter supercillium and more brown tones on breast/head/etc. Based on the guides, all non-breeding Rusty plumages should have obvious rusty edging on wings and are generally lighter overall. Bill appearance (flat vs downcurved as indicated in Sibley) appears to be intermediate and well within range of both species based on photos of definitive Rusty/Brewer's. It's very likely there's variation not shown in the guides and/or moult timing that can cause a Rusty to have this look at this time of year, but I don't have that knowledge. Other information: bill thickness at tip of nare was measured at 6.8 mm (if measured correctly). The only bill measurement mentioned in Pyle. Male Brewer's: 6.7-7.9, Male Rusty: 6-6.9. Female Brewer's: 6.3-7.5, Female Rusty: 5.7-6.6. Tissue sample available if someone has a sequencer lying around.