The easiest way to find out who is nesting in your nestbox is to ID an adult bird incubating, but incubation doesn’t start the last or nest to last egg is laid (depending on the species.) The location and nest construction are also great tips. For detailed descriptions of nest construction and egg identification, see Nest and Egg ID (also with links to photos of nests, eggs and young) and the nest contents ID matrix. U= uncommon, but it happens (e.g., about 3-5% of bluebirds eggs are white. Y=Yes. MB=may be. A “wreath” is a concentration of pigment on one end of the egg. More ID links below. For non-cavity nesting bird eggs, or eggs found outside the U.S.
| CLUE-> SPECIES |
White
|
Blue
|
Spotted
|
Wreath |
Shape
|
Gloss
|
Relative Size
|
Confused With |
| U | Powder | NO | Oval | Y | Larger | Finch, Starling | ||
| Bluebird, Mountain | U | Pale | Oval | Y | Larger | Finch, Starling | ||
| Bluebird, Western |
U | Pale | Oval | Y | Larger | Finch, Starling | ||
| Cream | Lt. brown or red. Dots or blotches | MB | Rounded | Little or no | Tiny | Titmouse | ||
| Chickadee, Carolina | White | Reddish-brown dots or blotches | MB | Rounded | Little or no | Tiny | Titmouse | |
| Chickadee, Mountain | White | Some no, some covered with dots | MB | Rounded | Little or no | Tiny | Titmouse | |
| Cowbird | or Grayish | Heavy, even brown/red dots. One replacement egg | MB | Rounded | Larger | House Sparrow | ||
| Blueish green | Sparing black dots | Oval | Slight | Medium | Bluebird | |||
| Or creamy or pinkish | Heavily scrawled/streaked with brown/purple/gray | Oval | Larger | Fewer markings than Great | ||||
| Flycatcher, Great-crested | Or creamy or pinkish | Densely streaked/scrawed with pruple, gray, red brown/olive | Often | Oval | Moderate | Larger | More markings than Ash, larger than House Sp | |
| Creamy or greenish | Irregular, fine brown speckles | MB | Oval | Slight | Medium | Cowbird, Great-crested, Nuthatch | ||
| CLUE-> SPECIES |
White
|
Blue
|
Spotted
|
Wreath |
Shape
|
Gloss
|
Relative Size
|
Confuse With |
| Y | Fine reddish-brown dots/blotches | Short Oval | Almost no | Small | Titmouse, House Sp, Chickadee | |||
| Nuthatch, Pygmy | Y | Uneven fine sparing speckles reddish | MB | Short Oval | Little or no | Small | Titmouse, House Sp, Chickadee | |
| Nuthatch, Red-Breast | Or creamy or pinkish | Heavily cinnamon/lavender/gray speckles | MB | Short Oval | Very little | Smaller than White | Titmouse, House Sp, Chickadee | |
| Nuthatch, White-brea | Or creamy or pinkish | Heavily cinnamon/lavender/gray speckles | MB | Short Oval | Very little | Larger than Red | Titmouse, House Sp, Chickadee | |
| Bold, liberal dull red brown or purple gray all over | ||||||||
|
Purple
Martin |
Pure | Slightly | Larger than Tree Swallow | |||||
| Pale blueish/greenish | Pointy | No | Large | Bluebird | ||||
| Pure, sometimes pinkish | Pointy | No or slight | Medium | |||||
| White | Some with faint sparing tiny red/brown speckles | Oval | Little or slight | Tiny | Chickadee, Nuthatch | |||
| Y | Irregular brown/purple/gray dots | Often | Rounded oval | Little or no | Tiniest | Not glossy like House Wren | ||
| White or rosy | Heavy reddish/brown flecks | often | Little or no | Tiny | Larger than other wrens, not glossy like House | |||
| White or pinkish | Numerous pinkish/brown specks | Often | Very | Tiniest | Bewick | |||
| CLUE-> SPECIES |
White
|
Blue
|
Spotted
|
Wreath |
Shape
|
Gloss
|
Relative Size
|
Confuse With |
|
|
Also see Nest ID Matrix (contents) and Egg ID Matrix (color, spots, etc.) descriptions of nests and eggs | PHOTO ALBUM with pictures of cavity nesting birds, nests and eggs. TABLE showing relative sizes of eggs, and egg photos side by side. To see other cavity nester bios/photos:
I would rather live in a world where my life is surrounded by mystery
than live in a world so small that my mind could comprehend it.
Harry Emerson Fosdick
