House Martins?

Well, during summer/fall there are many possibilities.

Can you further specify some things:
- How many birds together?
- Were all of them exactly the same?
- Did they bathe or only drink?
- Did you see these birds several times or just one day?
- Was the white patch in the tail visible from above or below the bird?
- You described them as small Blue Jays or Cardinals. Were they crested or masked?

In the meanwhile, the closest thing I have to a suggestion is a Barn Swallow. They are not uniformly navy, but they fit the slim/svelte description, they tend to stay in groups, and they are attracted to water sources. Their lighter underside could be what you described as "white patch". Plus, they actually have a white strip across their spread tails.

The above suggestion of Purple Martin is a good one but Martins aren't known to use bird baths. Also, Martins have a lot of plumage variation between ages/genders.

Eastern Bluebirds are another species you could potentially Google......they are not "navy", per se.....

Indigo Buntings and Blue Grosbeaks have no white and should both be heading out of your area before fall.....genders are very different.

Black-throated Blue Warbler are deciduous forest birds but they would be migrating through IL around that time. It's not unheard of to have them in the yard. Their genders are very different though. Plus, they are not slim/svelte.

That's all I've got for you. Any other blue passerines I ruled out for various reasons.

This post was edited by TMFF on Thu, Feb 14, 13 at 11:24

Also, the iridescence of European Starlings and Common Grackles could give the impression of navy but, alas, no white on their tails.

This post was edited by TMFF on Thu, Feb 14, 13 at 11:16

Wow, thanks for all the info! I'll try to answer the questions and give more descriptive info.

I only saw one bird at a time over several days in late summer /early autumn. (I do not recall seeing them earlier in the year)
Each one was the same.
I only saw them drinking.

Other birds were present each time, including sparrows, blue jays, cardinals, woodpeckers, flickers, maybe some finches

The white patch in the tail was only visible from above and behind as they/it were taking off.

The tail was very similar to a cardinal in shape, no points or edges. The head was pretty smooth, not much of a crest, if any.

The color was a very dark navy blue (not black), not very iridescent, but consistent though I could not see the underside very well.

I looked at online images of the different species mentioned. and none really match.

I also have several birding books and so far no matches.
Purple martin is close, but the tail was very different and in the images look more iridescent.
Barn swallow has too much color, white breast, and forked tail
Eastern bluebird has too much other colors, not dark enough and stubby shape
Indigo bunting is too stubby and the color is much lighter
Blue grosbeak has too many other colors and is not dark enough, some pictures show them fairly slim
Blue warbler is too stubby and has too many other colors.

Hmm, I'll keep looking at books too, but I really appreciate the info, wish they fit better.

Thanks!

Oh, and European starlings are too rounded and not consistently dark blue.

Hmmm...the mystery deepens!

One thing to consider is that in the late summer heat, birds will pull their feathers close to their bodies and appear slimmer than they do in "ideal" photos.

How was this white tail patch shaped? Was it at the tip, in the middle, or at the bird's rump?

Funny that the species your bird(s) most resembled is the one species it couldn't have been (Purple Martin). They never perch to drink. Well, and they don't have white on their tails.

Are you sure it wasn't this? Hehehe...okay, this is just for fun.

Yes, the mystery deepens!

My neighbor has several bird feeders, and I have a large old concrete birdbath that I was cleaning out and refilling every couple of days during the record breaking hot summer. It was not uncommon to see 6+ different birds at the bath at one time. The area is sheltered with many mature trees and shrubs, especially spruce, hemlock, lilacs, viburnums breaking the winds that come in from the west.

I live in an 1895 house in an old rural town (Big Rock, IL, Est 1834), with farm fields nearby as well as some prairie woodlands that have never been developed (aka ruined, LOL). I have seen other critters that I have not seen in decades when I lives 25 miles closer to Chicago. Preying Mantis, Luna and some Sphinx moths, even a Hellbender salamander digging into my burn pile (got relocated to the creek bank). And I'm still a novice.

I'm wondering if these variables might have some species passing through at times that might otherwise not be considered "regular" In the Metro Chicago area?

Just looked through a 1936 copy of Pearson's Birds of America and came away with few ideas.

Purple Grackle seems similar, but what I saw was slimmer and not as iridescent. Similar thoughts about Blackbirds, Grackles and Purple Martins.

The shape of the tail reminded me of male cardinals, but the birds were a bit smaller, about 3/4-7/8 the size.

The white tail patch was only visible when the birds started to take off. I saw this more than once. It was kind of in the middle of the rump as opposed to the end of the tail. From what I saw of the birds, the underside was certainly a dark color as well.

I looked through a few other birding books I have between the first and the last sightings, and nothing listed matched. I wondered if it/they might have been a lesser mentioned subspecies or a juvenile.

Interesting....

After reading this on Purple Martins, I think you may be right about the one it couldn't have been possibly being the right ones, especially if they were migrating and desperate for water in the drought. Note the mentions about the concealed white tuft on sides and rump. I've found a few pictures that show the wings folded in such a way that the tips look more like a tail extending out. From my vista of 20-30 feet this could be...

http://animals.nationalgeographic.com/animals/birding/purple-martin/

You have a better chance of having seen a blackbird with a leucistic rump patch than a Purple Martin at your bird bath. Especially over the course of several days.

Location/behavior is the number one factor in IDing a bird. Plumage can vary and can also be deceiving in certain lighting, especially from a distance.

I live in Kansas where the sun is very bright and the clouds are few. Crows often appear to have white patches as the bold light reflects just right off of their wings and backs. The American Crows here are often mistaken by novice birders as having yellow bills! Of course, these birds are actually solid black; bill included. Reflection really plays tricks with visible light.

Martins swoop down and skim the tops of bodies of water for drinks. They drink on the wing. The drought reports are indicating they are sizing down to swimming pools when desperate. They do not perch for water. The literature states they wouldn't even take notice of a birdbath.

This post was edited by TMFF on Fri, Feb 15, 13 at 14:38

Hmm, well, with me being a novice, I wouldn't know that Martins don't perch, and drink on the wing.

I agree that location/behavior are the best way to identify a bird.

The birds I've seen or the one I saw was seen several times from both inside and out, sunshine and shade. The color was definitely a dark navy blue, with no iridescence. Not black like I see on the RW Blackbirds in some marshes I drive past. Dark bill and eyes. Whitish patch on rump visible when taking off. A little smaller than an adult male Cardinal, but similar shape without a crest.

I've been able to discern between a Downey woodpecker, Northern Flicker, and Red Headed woodpecker with no problem.

I was looking through books trying to identify these dark blue birds/bird and didn't see a match in between sightings.

I'd guess what I saw was a variation of some type, but not sure if it was a crow, grackle, blackbird, etc.

I'll sure be looking for them this year!

Yes! And if you see them, please let us know on here! I am terribly curious now because I am coming up fruitless on this search.

I had one more possibility to throw out there (since we are simply stumped): have you looked at the Eastern Kingbird? Yes, they are white/grey underneath, but they are a dull black above that could give a midnight blue impression (it's a stretch). It's just that they have a very conspicuous white mark on their tails and are approximately the correct size and shape. Just a thought since I am more or less useless at this point.

Don't feel badly, I've looked through 5 books and really couldn't come up with a good one either. The Eastern Kingbird pIctures I've seen all show too much white. I'm thinking it might have been a Brewers Blackbird based on some of images that I've seen of them as a dark bluish-gray, just not as iridescent as some. Female, or rusty variety?

Mockingbird is my guess. The white flash is really noticeacle when they take off. I have some colour deficiency in the blue/green ranges and they look blue to me but I guess others say grey.

Here is a link that might be useful: avian web

Hmm, very interesting! Also shrikes seem to be a possibility. I didn't get a good look at the underside, but didn't see a conspicuous very light underside. Definitely a white patch on the tail when taking off, don't recall seeing any white on the wings.

Mockers love scrub and brambles, it's where they chose to build their nests. Mockers are a permanent part of my rural habitat and are an almost daily sighting in our bird population. They are territorial and have a routine of scoping out their chosen breeding and fledging sites against interlopers. The males will often perch in high places so they can see over their land to ward off intruding mockers. That means a pair is usually present during summer. They are also not shy about coming near human habitation, and show up at our feeder areas to eat and roost. Birds like shrikes you don't usually see at feeder areas. Hoping you can get a better look at them as the season gets into swing this year and if they're mockers and have nested near your eyesight last year, chances are they'll do so again this year. Good luck in identification. BTW one doesn't always notice all the identification clues, even the obvious ones at first. It has taken me years to build up my 'library' of identifying features for bird species and I'm still learning.