[Warbler in Patagonia AZ (Mexican Border)]

Yeah, i could see that. Just never noticed one before with such a distinctive wanna-be-a-Nashville/Connecticut/Magillivray's gray hood.

Photo search sure shows some birds with that, though. Thanks.

[Warbler in Patagonia AZ (Mexican Border)]

Keep coming back to Nashville Warbler on this one, but December would be unusual (but not unprecedented) for here.

Also, that yellow is the wrong hue and those stripes just don't seem right for Nashville.

[Costa Rica Osa Peninsula]

White-throated Shrike-Tanager.

The Caribbean side has a yellow back/rump as pictured in Stiles & Skutch Birds of Costa Rica (Plate 47 #1) and Garrigues/Dean The Birds of Costa Rica p.283.

But the Pacific side has a black back/rump as in your picture.

[Hawaii Yellow Finch just aint right]

Seen at Big Island Country Club (Now Makani) on Big Island early April. Seems finchy with sharp yellow/white chest demarction. But face and beak not good for Palila. Bad shape & no eye ring for White-eye. No facial of chest markings for Yellow-fronted Canary or Saffron Finch. Odd well-demarcated light rear cap.

[Swamp birds.]

1. Probably Solitary Sandpiper, but that tail barring really speaks to Spotted. Both have spots on back. Facial pattern makes it a prob Solitary.

2. Northern Shoveler. Nothing else with that profile.

3. Looks like Mallards in back. Wood Duck in front.

4. Odd sparrow. That is a crazy long tail. Has to be a trick of the eye, or weird angle or something. Any additional pic would help.

[west Houston Kingbird?]

I agree. White tail-tip is the give-away.

[?? Duck]

First thought was Fulvous Whistling-Duck with that long, stretched neck, but no plumage has that side pattern. Looks to me like female Northern Pintail. The one stretching gives a distorted body shape.

[Sparrow & Warblers]

1. Lincoln's Sparrow - Nothing else has that crisp black on brown chest pattern.

2. Possibly Bay-breasted, but total lack of any eye stripe is unusual. I'd vote Chestnut-sided Warbler. - c.f. Peterson Warblers first fall Chestnut-sided Warbler p. 239

[Empid--Window Strike]

Looks like Dusky Flycatcher. Maybe first year. Rounded head. Short primary projection (as far as i can see). Primaries w/low-contrast striping.

A pic w/a natural lie of the primaries showing a long projection may turn this into a Hammond's Flycatcher, but that head is very round.

[Two hummingbirds near Quito Ecuador]

I feel the back shot one is a Sparkling Violetear, but never got a good look at the breast. Not too many have that thin blue line extending so far around the neck.

Is it possible that these are both the same species?