Bird Quiz: Eggs

Photo: Julie Falk/CC BY-NC 2.0

With several egg-involved holidays coming up, we decided to take a different tack on our usual bird quizzes, concentrating this time on those beautiful ovoids from which chicks hatch. Forget your typical chicken egg. What do you know about those the brown-headed cowbird lays? How about ostrich eggs?

Take our quiz, then brag about how egg-cellently you did. (Sorry, couldn’t resist.) Scroll past the image below for the answers.

1. True or False: Cowbird eggs come in many different shades, including white, blue, and green.

2. How long, on average, is a rufous hummingbird egg?
a. 1/8 of an inch
b. 1/4 of an inch
c. 1/2 an inch
d. 1 inch

3. How large is the average ostrich egg, the biggest of all eggs?
a. Under 3 pounds
b. 3½ to 5 pounds
c. 6 to 10 pounds
d. More than 10 pounds

4. True or False: Blue-footed boobies defecate on their eggs during incubation.

5. Which hummingbird species laid the smallest egg on record?
a. Vervain hummingbird
b. Broad-billed hummingbird
c. Ruby-throated hummingbird
d. Anna’s hummingbird

Photo: U.S. Fish and Wildlife

Answers
1. True or false: Cowbird eggs come in many different shades, including white, blue, and green.
True. In fact, some might consider the eggs of these nest-stealers—they take over those of red-winged blackbirds, ovenbirds, even yellow warblers—nicer looking than the drab birds they become. Egg hue can range from grayish-white to bright blue (think a robin’s egg) and most are speckled, according to Cornell Lab of Ornithology’s Nest Watch.

2. How long, on average, is a rufous hummingbird egg?
C, 1/2 an inch. These west-coast birds lay up to three eggs per clutch. In addition to being just half an inch long, these eggs are just a third of an inch wide. They’ve got to be small, considering where they sit for the two-week incubation period: “Finished nests are about 2 inches across on the outside, with an inner cup width of about an inch,” according to Cornell’s All About Birds.

3. How large is the average ostrich egg, the biggest of all eggs?
B, 3½ to 5 pounds. That equals two-dozen chicken eggs, by volume, according to the American Ostrich Association. The typical ostrich hen lays about 60 eggs per year, each of which takes six weeks—42 days—to hatch.

4. True or False: Blue-footed boobies defecate on their eggs during incubation.
True, much like the Northern shovelers of our most recent bird quiz. Whichever parent is incubating the eggs—which don’t sit in a nest, but on the bare ground—create a poop barrier, what Cornell describes as a “circular wall of excrement.”

5. Which bird species laid the smallest egg on record?
A, vervain hummingbird. According to the Guinness Book of World Records, “two specimens measuring less than 10 mm (0.39 in) in length weighed 0.365 g (0.0128 oz) and 0.375 g (0.0132 oz).” The eggs of both ruby-throated and Anna’s hummingbirds are typically 1/2-inch long and 1/3-inch wide.