Yikes!  Has anyone looked for this any further?

I certainly don't mean to question the birder's ability, since of course this could have been a Gyrfalcon!  However, the description provided is also very strongly indicative of a juvenile Northern Goshawk, and the marks noted do not indicate how this similar species was ruled out.  I have to mention - I have no experience with Gyrfalcons, but I am familiar with Goshawks and know the field marks of both.  The field marks can be very similar for a juvenile NOGO and a GYRF.  If anyone goes to look, they should consider the following (quotes are marks noted from Stacy):

"about 22 inches" - The species are essentially the same size and both have a bulky appearance.  Not a good mark to distinguish by.

"long squarish falcon tail" - this is a toss up but leans toward GYRF.  Square versus rounded can be hard to see, especially on a perched bird, but at a distance of 20-40 feet the length of central feathers could have been seen.  It was not noted.  Accipiters central tail feathers are longer than the outer ones (especially noticeable on hatch-year birds), which can give them a rounded tail appearance.  Squarish would indicate having an even length, which is a good mark - if the feathers are not worn and are not ruffled or messed up!  However, noting it was "long" tends to confuse this id, unless there is more info.  GYRFs have a long tail, especially compared to other falcons, but NOGOs have a relatively longer one.  When compared with wing primaries, Accipiters' long tail length is really apparent on standing or perched birds.  A description of tail's plumage could also help.

"gray/brown streaked and mottled" - Again, a toss up for a field mark, as this description also fits juvenile NOGO.  It may help to note where the streaking was.

"whitish strip over the eye" - Could also be either species.  The eyebrow stripe on juvenile NOGOs is usually distinct, and can be prominent enough to be seen well at a long distance.  This narrows it down to both species!

"long legs" is especially typical of an accipiter.

***  For some reason Stacy did not mention important facial marks to look for - eye color, eye ring, and facial pattern (cheek).  At such a close range the GYRF's strong eye ring should be very apparent (prominent on all falcons).  And the eye color, which would be yellow or yellow-orange on a juvenile accipiter, versus a very dark brown or black on the GYRF.  Eye ring and eye color are both excellent field marks to look for on these two species.

She mentioned it was nothing she was used to seeing, but Goshawks are also very uncommon in Md (except maybe far western Md), so I found it odd not to mention how NOGO was ruled out.

Hopefully it will stick around and maybe she can get a photo or someone else can relocate and confirm it!  Wish I was closer but I have no chance to look for this bird anytime soon.  I have to settle for looking around the yard until then...

Cheers!
Jeff Shenot
Croom  Md