The last of our three pairs is a couple of blue birds that are found in the same basic habitat – brushy fields and wood edges, often not too far from water.  The smaller of these birds is about sparrow-sized and all a dark, but iridescent, blue, and frequently sings from the very tops of trees.  Indigo Buntings,

have a double-phrased song that I learned as “fire, fire, quick, quick, put-it-out, put-it-out..”, and as I learned when searching for these in my younger days, seem to be somewhat ventriloqual – they never seemed to be where the sound was coming from.  The female can be confusing to even fairly experienced birders, with her plain brown color, faint wingbars and seed-eater’s bill that’s heavier below than above.  With a bit of an effort, she can be turned into all sorts of other birds..

The other bird here, the Blue Grosbeak, looks at first rather similar, but has some key differences.

The first, of course, is size, but unfortunately size can be very hard to estimate in the field, especially with no good comparison nearby.  Grosbeaks have a relatively much larger bill than buntings, but this isn’t as straightforward as the Hairy/Downy Woodpecker beak comparison.  It’s a lot more of a “feeling” sort of thing for most of us.  The most useful thing to look for are the heavy, buffy brown wingbars.  Even on the female, they are quite noticeable. and make identification much easier.  Blue Grosbeaks have a very different song, as well, which can confirm your sight ID.  The burry, warbling Robin-like song is not too far off the Orchard Oriole’s song, but it doesn’t have the cartoonish buzzing and boinging overtones that make the Oriole’s song so reminiscent of a Bobolink’s.  Unlike the Robin’s song (or the Bunting’s song), these warbling songs aren’t formed of separated phrases with a short pause in between, but are sung as a single longish, variable production.