Wrote to Dan Harville, Master Hummingbird Bander in this area. Here's what he wrote.

Christine Southwick
N Seattle/Shoreline
clsouthwick at pugetsoundbirds.org
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

---------- Forwarded message ----------
Date: Fri, 11 May 2012 14:46:41 -0700
From: Dan Harville <dharvill at u.washington.edu>
To: 'Christine Southwick' <clsouth at u.washington.edu>
Subject: RE: [Tweeters] R. Hummingbird: Injured? Sick? Tumor? (fwd)

Doesn't look like a tick to me. It looks like he may have had an injury up
there and it's possibly scarring. I've seen that happen occasionally on the
bill itself where you get a big growth. One that I caught a year or so ago
with a growth in the middle of the maxilla (and the bill was slightly bent
as if it had cracked) I retrapped later (next year maybe?) and the growth
was gone. As long as the bird seems active, it doesn't look like it's
hurting him at all.

Dan

>
> ---------- Forwarded message ----------
> Date: Fri, 11 May 2012 14:22:11 -0700
> From: Kimberly Mason <kz at tds.net>
> To: tweeters at u.washington.edu
> Subject: [Tweeters] R. Hummingbird: Injured? Sick? Tumor?
>
> A male rufous hummingbird showed up at my feeder yesterday, something
> is wrong with him. There is a lumpy growth at the top of the base of his
beak
> and feathers missing on his head. He has plenty of energy and is running
> every other hummingbird off the feeder.
>
> Anybody know what's wrong with him? There are two pics on the top row,
> right side, of the following page:
>
> http://www.almostdailynews.com/galleries/hummingbirds/
>
> --
> Kimberly Mason
> 360-269-5017
> Cinebar, WA
> The (Almost) Daily News