- Adult female Ruby-throated Hummingbirds (RTHU) are 15-20% Larger than
adult males
- MASS: About 3-4g (a nickel weighs about 5g); may nearly double mass
prior to migration by putting on extra fat
- LENGTH: About 8.5cm (3.5") from tip of bill to tip of tail
- FLEDGLING SIZE: Hummingbirds are full-grown when they leave the nest;
baby hummingbirds cannot fly
- WING BEATS: About 60-80 times per second in normal flight, up to 200
times per second in courtship dives
- SPEED: Normal flight about 25mph; up to 65kph (40mph) in a courtship
dive
- FLIGHT MUSCLES: Make up about 25% of RTHU's weight (compared to 5%
pectoral muscle weight in human beings)
- HEARTBEATS: About 250 times per minute while at rest, about 1,220
per minute while flying
- HEART SIZE: About 2.5% of total body weight
- NEST SIZE: Inner diameter of about 4cm (1.5"); the outside of
the nest is about 6cm (2.25") tall.
- EGG SIZE: 8mm x 13mm (.25" x .5"), roughly the size of
a small jellybean
- EGG COLOR: White, non-glossy
- Most hummingbirds die within their first year; those that don't probably
live an average of 3 years or so
- Chicks are naked and about 2.5cm (1") long at hatching. Mass
is doubled each day over the first several days.
- BODY TEMPERATURE: 40.5 degrees C (105-108 degrees F)
- A typical RTHU has 940 feathers
- NEST MAKEUP: Spun by the female from spiderwebs and plant material,
camouflaged with bits of lichen, lined with plant down
- NEST LOCATION: Eastern United States and southern Canada in mixed
woodlands, orchards, suburban areas with shade trees, etc.; often on
an "edge" between open area and woods
- NEST SITE: 2-18m (6-50') above ground, usually attached to a small,
downward-sloping twig and often near water; nest site--but not the nest--may
be used from year to year
- NESTLINGS: NUMBER OF EGGS PER NEST: 2, sometimes 1, almost never 3
- INCUBATION: About 16-18 days (perhaps longer in cool weather), by
female only
- BROOD PERIOD: About 21 days (perhaps longer in cool weather), by female
only
- FEEDING OF YOUNG: Female collects nectar and tiny insects in her crop,
then regurgitates the slurry into mouths of nestlings
- AVERAGE AGE: RECORD AGE: The oldest known RTHU is listed at about
9 years
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