You don't say where this window is ....

Maybe a "silky Flycatcher"?

http://www.wqed.org/birdblog/2011/04/09/one-of-a-kind/

Melanistic cardinals are more dark brown than black
http://www.reddit.com/r/whatsthisbird/comments/22vc93/cardinal_with_dark_plumage_is_this_common/

EDIT: OH DUH! The location was in the title of the post, not the body. So I doubt what you saw was either a Stellar's Jay or a silky flycatcher, those birds range in the western part of the US but wouldn't be seen in SC.

It must have been a melanistic northern cardinal.

You don't say what state you are in - but in the west there is the Mountain Jay, or Stellar's Jay, which has a black head and a dark blue body. The black extends well down past the neck onto the shoulders.

Some subspecies have more black than others, for instance:

While the silky flycatcher does LOOK like a black cardinal to a pretty high extent,

{{!gwi}}

it is also a Western bird and I would be surprised to see it at a feeder - unless it was a meal worm feeder? They only eat flying insects and berries, mostly mistletoe berries. I guess I would be surprised even to see one at a meal worm feeder, but maybe they would eat meal worms if offered.

There is also the possibility of a melanistic Stellar's Jay - assuming you're out west somewhere

In what part of the country are you located?

This post was edited by zensojourner on Thu, Aug 28, 14 at 15:23

zone 7 in South Carolina around the city of Powdersvile, west of Greenville I'm thinking like the two of you, that it is a melanistic cardinal with pigment darkening, he returned about an hour earlier this evening and I was able to get 3 pictures but the one above, is the only one that that has any clarity I have one of a female taken about three hour later that I will try and post in a moment. the one I took here is the same bird, but in better light and the beak is blackish orange. This picture is about a foot off the window, it looks a little like he's or she's in the shade, but as you can see the female bird show her colors well.

This picture is a female cardinal, taken about 3 hours later. I don't know what picture software guys use, but the one I use, Irfanview shows the info on the picture including camera setting. I'm using a Kodak m550 camera

No Black cardinal today, but today was very exciting, just looked what showed up, I guess he is on his way home. I'm 66 years old and lived here in upstate South Carolina all that time, but this is a new bird to me blue grosbeak, and he stay long enough for me to have some fun. Took several video with my flip-video, absolutely beautiful.

that is a juvinile male. All his red feathers are just starting ro grow in. My young birds often practice their fluffing, puffing and working the crest on the top of the head, making them look bushier than usual. I am 100% certain you have a young male there.

It could be anything. I spotted a Phainopepla on a power line one day here in central Oklahoma. Photo by Steve Zamek

I have watched the 'black cardinal' from the beginning post, and it is a cardinal, no longer black though, but still very dark brown, yes there is a red tint to all the feathers, I'm inclined to think it's a male too.

He is a loner, never comes to the feeders with a group like most do. He is aggressive and runs the other cardinals off, no matter how red they are. Most of the time he just waits till the other cardinals are gone. he will feed with all the other birds as long as they don't get to close.

I have a video where you see a female cardinal come and land on the cast iron post the feeder is on, while the dark cardinal was at the feeder, and it did get mean with the female, repeatably flying up at her till she left. The beautiful female with the brown to tan, beside the the dark cardinal his brown looks black compared to her. I've not seen him near a juvenile male yet. He's a beautiful bird, at any rate. I have been trying to take the video and get some snapshots from it, my Kodak is not like my Flip video, my Flip has software built in for doing anything, including snapshots.

Here's a picture from a set a few days ago, not good quality, and in the shade, I'll try and send the other three or four. the only way I have to tell him from any other, is that the dark color shows him up, even if he is flying across the yard to the feeder.

first one