Recently a five-year-old friend asked me, “What’s the biggest bird?” and I was reminded of our fascination with the biggest. To him biggest equated to best.
Since I’m often asked this question, I had a ready answer: the bald eagle. But what about, say, the five biggest birds that are commonly seen on Whidbey Island? Care to take a guess?
I quizzed my husband, a fairly experienced birder, and off the top of his head, he suggested (in this order) 1) Bald eagle 2) Great blue heron 3) Red-tailed hawk 4) Turkey vulture 5) Great-horned owl.
Figuring out the biggest common birds isn’t all that easy. Do we gauge by length or weight? Do we factor in wingspan? Since all birds are designed to be very lightweight, I wondered if there would be much difference between, for example, the bald eagle and the red-tailed hawk.
What about a long skinny bird like the great blue heron? Birds are measured from the top of their head to the bottom of their toes. If we only considered a bird’s length, the heron would be the biggest at, on average, nearly 50 inches. Whereas the bald eagle only stretches to 39 inches. Clearly we can’t award the biggest bird prize to the long gangling heron.
Wingspan also doesn’t seem the best yardstick of the biggest birds. The length of the wings is determined by long-distance flight needs, mainly migration. Swallows and terns have some of the longest wings, in comparison to body length, for just that reason. The bald eagle and the great blue heron are neck-and-neck in regard to wingspan, with the eagle having a slight edge.
So, that leaves weight as our determiner of biggest bird. In this category the bald eagle clearly wins at 10.5 pounds. Second prize goes to a sleeper, the common loon, which weighs in at a little over nine pounds. And third prize to the Canada goose — gads, how could we forget that eight-pound mother?
Then we drop down to five and one-half pounds and find the great blue heron, followed by the double-crested cormorant at four pounds. Continuing on down the list there is a close tie between the turkey vulture and osprey at three and one-quarter pounds.
What happened to the red-tailed hawk? Several additional birds, including the great-horned owl and common raven, surpassed it.
Many birds and especially eagles, hawks, owls have significant sexual dimorphism, meaning one sex is larger than the other. For example, the female bald eagle can be 20 to 30 percent larger than the male. So technically I should have told my young friend that the female bald eagle is the largest common bird.
What if we widen our criteria to include some less common birds? Take those wild turkeys often seen on Bayview Road. They outweigh the bald eagle by over six pounds.
Every winter trumpeter swans visit Whidbey. At 25 pounds they beat out the bald eagle by two and one-half times.
Even though the swans, turkeys and also the American white pelican clearly outweigh the bald eagle, some of us have a hard time accepting any of them as the biggest bird. Perhaps our claim of “biggest” also needs to include something majestic, something to make the bird the best, not just the heaviest. That would explain why we tend to put the red-tailed hawk so high on the list.
I’m sure my five-year-old friend wanted the bald eagle to win and I’ll have to admit that I did, too. The regal eagle perched atop a tall spire, a bird that fought off endangered species status and rebounded to a large healthy population, certainly deserves the prize.