[What's the butterbutt?]

Yes. Yellow-rumped Warbler (Myrtle)

[September Sandpiper in California]

Welcome to the WhatBird forum AvocetAngler.

[which thrush?]

Most likely a Hermit but the buffy breast gives me pause. Thanks.........Nova Scotia this morning

[Yellow Warbler?]

Nova Scotia this morning. Thanks

[Warbler, back and side only S.WI]

I won't be doubting you folks. Blackburnian it is. I find that if I attempt an ID on this site and I am wrong, (which I often am) the field marks that are given for the correct identification tend to sink in and stick.

[Warbler, back and side only S.WI]

I think I see an orange foot, so Blackpoll for me.

[Painted Bunting Question]

Gotta be young with that fleshy gape.

[Which Vireo?]

Thanks to all for taking the time to look and explain how you arrived at your conclusions. These tips will help.

[Which Vireo?]

Thanks, IKLIand

[Which Vireo?]

I just returned from a hike in Halifax, Nova Scotia.  I would like a little help before I report. Pics #1 & #2 are the same bird and I think Philadelphia Vireo or Warbling. Either would be a first for me. Pics #3, #4, and #5 are the same bird. There is such a yellow/green wash over the bird from the foliage, I'm confused. I don't expect an ID from pic #6, but you folks on this site always surprise me. Thanks for taking a look. 
 

[Sandpiper]

You are correct. Solitary

[Traill's or Pewee in Houston?]

I see. Better wait for the experts.       Note: an EAWP would also have a longer primary projection.

[Traill's or Pewee in Houston?]

Perhaps an Eastern Phoebe (EAPH)with a round,dark-capped head, white throat, and black bill.

[Hawk in Maryland]

The pale translucent crescent across the outer primaries suggests a Red-shouldered Hawk. Wait for the experts.

[Two warblers in a tree]

Lots of Yellow Warblers and Common Yellowthroats along the hiking trail at Crystal Cresent Provincial Park in Nova Scotia this morning. I am unsure of these two warblers and could use some help. I believe the photos are of the same two birds but can't be sure. Thanks for taking a look. 

[Help with blurry longshots]

Thanks, Peromyscus. I'll wait and see if anyone can pin down the first bird before I submit my list for today.

[Help with blurry longshots]

Sea watching from a point this morning in Nova Scotia. A great morning once the fog moved off with no wind and calm seas. Many Shearwaters flew low to the water, and I managed a couple of photos of smaller birds that overtook and passed the Shearwaters. They both had rapid wingbeats.  The first bird may be a Murre of some kind or a Razorbill and the second an Atlantic Puffin. Can you folks confirm or suggest something else? Thanks     (oh, The photos have been cropped but not altered. )

[Confirm Wigeon?]

confirmed

[Black head, very vocal, white v tail]

Please disregard my guess but not my welcome. Tree Swallows don't have white tails.

[Black head, very vocal, white v tail]

Perhaps a Tree Swallow. They like to sit on cables and their song is kind of tinkling. Welcome to the WhatBird community. 

[Bad photo--Coccyzus sp?]

I was thinking Sharp-shinned.

[Merlin says Willow flycatcher]

Nice pic!

[Help with bird ID please]

Might be a Say's Phoebe as per Peromyscus as I think there is visible rufous showing under the tail in the 4th picture.

[Help with bird ID please]

The first bird is a Lark Sparrow distinguished by its unique bold facial pattern. The second bird may be a House Wren with its plain brown crown, thin slightly curved bill, and lack of discernible eyebrow. The third bird looks to be a flycatcher but I'm not confident, perhaps a Willow. (just a stab so wait for the experts)

[Ipswich ?]

Thanks, @Avery I was leaning adult (eastern) as well and will report as such.