Bluebird and Small Cavity Nester Conservation
Sialis - Bluebirds and other small cavity nesters
 
bluebirds

eggs

Small Cavity Nester Egg ID Matrix

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. see the searchable database at the Royal Alberta Museum Virtual Egg Exhibit.

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 wtih 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
Cavity nester photos of nests eggs and young

Cavity Nester Nests, Eggs and Young Photos and Bios. Also see Nest ID Matrix (contents) and Egg ID Matrix (color, spots, etc.)


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


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May all your blues be birds!

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Last updated March 24, 2016. Design by Chimalis.

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