3 g0.11 oz
An adult ruby-throated hummingbird weighs about 3 g (0.11 oz, or 0.007 lb). Most weigh 2 to 6 g, with females a little heavier than males. The top of that range comes before migration, when a bird can nearly double its weight in fat to fuel a non-stop flight of about 800 km (500 mi) across the Gulf of Mexico.
| Fattened for migrationOver 6 g, nearly double its lean weight | 6 g0.21 oz |
|---|---|
| Adult female, averageFemales are the larger sex | 3.8 g0.13 oz |
| Adult male, average | 3.4 g0.12 oz |
| After crossing the Gulf of MexicoA bird that set out at over 6 g | 2.5 g0.088 oz |
| Newly hatched chick | 620 mg0.022 oz |
Field guides give a range of 2 to 6 g (0.1 to 0.2 oz) for adults, and a typical bird weighs about 3 g (0.11 oz). Females are slightly larger than males, averaging about 3.8 g against 3.4 g for males. The bird is 7 to 9 cm (2.8 to 3.5 in) long with a wingspan of 8 to 11 cm (3 to 4.3 in).
Weight changes a lot over the year, and even over a day. Most of the variation is fat. A bird about to migrate can carry several grams of it, while one that has just finished a long flight may be close to its lean weight or below it.
Ruby-throated hummingbirds breed across eastern North America and winter from Mexico to Panama. In spring, many fly straight across the Gulf of Mexico from the Yucatán Peninsula, about 800 km (500 mi) of open water with nowhere to feed, a flight usually put at 18 to 22 hours. Many others skip the crossing and travel around the Gulf along the Texas coast.
To manage it, a bird feeds heavily on nectar, insects and spiders and can go from about 3.25 g to over 6 g in roughly a week. Journey North reports that such a bird may land on the US coast weighing only 2.5 g, having burned more than half of its departure weight.
A study of 2,729 hummingbirds banded on the Alabama coast in autumn 2010 to 2014 found they arrived carrying on average 0.92 g of fat above their lean weight, and up to 2.8 g. From those fuel loads, Theodore Zenzal and Frank Moore calculated an average potential flight range of about 2,260 km (1,400 mi), more than enough to cross the Gulf. The fattest birds could in theory have flown over 4,900 km, while some carried enough for only a few kilometres.
The female lays two white eggs, each about 12.9 by 8.5 mm and roughly 0.5 g, in a nest about the size of a walnut shell. She incubates them alone for 12 to 14 days. A newly hatched chick weighs about 0.62 g, so three of them weigh less than one US dime.
Chicks grow fast: their mass doubles by day three, doubles again by day five and again by day eight. They leave the nest at about 20 to 22 days old, and the female may raise a second or even third brood in the same summer.
A typical adult weighs about 0.11 oz (3 g), and the full range is about 0.1 to 0.2 oz (2 to 6 g). In pounds that is roughly 0.007 lb.
Females are slightly heavier and larger, averaging about 3.8 g against 3.4 g for males. Males have the red throat and slightly shorter bills.
Yes, many do, especially in spring, flying about 800 km (500 mi) non-stop in roughly 18 to 22 hours. Many others travel around the Gulf instead, along the coast of Texas and Mexico.
It can nearly double its weight in about a week, going from around 3.25 g to over 6 g, almost all of the gain being fat. It burns most of that on a long crossing and can land weighing as little as 2.5 g.
A ruby-throated hummingbird egg weighs about 0.5 g (0.02 oz) and is about the size of a small jellybean. The chick that hatches from it weighs about 0.62 g.
Last checked October 2, 2026.
