In the Art Journal sub-forum on WetCanvas.com, there is an 'October Sketchbook Challenge' that involves choosing a sketchbook and committing to fill it during the month of October - a very good way of adding motivation to get more sketching done. So I decided to do a 50-page (100 sides using front and back of the page) Pentalic Nature Sketchbook with the theme Backyard Birds and Nature, though I qualified 'backyard' to include interesting areas near our house as well as physically in the yard. Here are some of the sketches included in that book.
The first three images here are graphite sketches of American Goldfinches in various poses, feeding in our yard. They were drawn from a videotape I shot of them, which I stepped through and stopped when I found an interesting pose. I gave myself 5 minutes or less to do each sketch.

The previous page is the good old American Crow, which has a unique bill/beak structure which I was having trouble with. So I shot a crow video and sketched three pages of just the bird's head and bill - this is one of the pages.
The following page is a Wilson's Snipe (yes, a few species of snipe do really exist). They are not waterbirds per se in that they can't float on the water - in this image from a reference photo it looks like the bird is floating, but it is actually wading in the water up to its belly. So, it's more of a shorebird than a waterbird.
The next two pages are of the Bushtit, which has to be in the running for the cutest little bird out there (in North American at least). They are quite small and look like little gray cotton puffs with beady eyes and a long tail. They feed in chittering/chattering flocks.
The next bird is a Brown Creeper, whose name comes from its feeding habit of creeping nervously up a tree trunk or branch eating small bugs. They are very well camouflaged.
The next page is an Acorn Woodpecker. This species is very rare in our part of the world, but one showed up in a city park a couple weeks ago and stayed for a few days. They are unique in that they collectively gather food (acorns primarily, of course) and then store it in a granary tree which is shown here. They drill appropriately-sized holds for the acorns and then wedge them in so tightly that even squirrels can't extract them. The stored acorns then provide food for the birds, who live communally in an extended family group. And yes, they do look rather clown-like in real life...!
The following duck in flight is a Northern Pintail, a very elegantly handsome species so named because of its longish, sharp tail. This is a drake (male).
The next bird is a Purple Finch female. The male is colorful with wine-colored head and upper breast whereas the female is a drab light brown. There are structural differences you get to know between this bird and the House Finch female, which is very similar. The most obvious difference is that the female Purple Finch shown here has a light-colored 'supercilium' (eyebrow) which the female House Finch lacks.
And finally for this group, a Pied-billed Grebe, an interesting waterbird species that is commonly found on freshwater ponds and sloughs. This species has the unique ability to partially submerge if needed to make itself less conspicuous and of course it is an accomplished underwater diver and swimmer since it obtains its food under the surface of the water.