FOAM LAKE
BIRDING
No. 177
Our flower beds are in full bloom
and with that an accompanying increase of flower loving wildlife like
butterflies, bees and of course one of nature's wonders, the hummingbirds.
Different orders of birds differ
significantly from other orders of birds ("order" is the first
classification of birds into different groups).
For example, ducks and geese, although different, are similar enough to
belong to the same order. The same goes for the robin and raven. On the other hand, ducks and robins are in
different orders. However, when it comes
to being different the hummingbirds "take the cake" as it were. Here are some of their unique
characteristics:
1). As a group they
are the smallest birds in the world. The
smallest is the Bee Hummingbird of Cuba; the largest is the robin-sized Giant
Hummingbird of South America.
2). The wing
structure is modified allowing for much greater rotation at the shoulder giving
the hummer greater manoeuvrability in flight and the wrist joint is fused for
greater stability at high rpm.
3). They have oversized breast muscles capable
of driving the wings up to 80 flaps per second.
These last two characteristics allow the hummer to fly backwards,
sideways, straight up and down, hover and even fly upside down. No other bird can do this. By comparison a crow flaps its wings about 4
times a second; a House Sparrow about 10 and all have to be moving forward to
stay aloft. The rapid wing beat produces
a humming sound from which the birds get their name of "hummingbirds".
4). Flying takes a
lot of energy and the hummers need it in spades. In fact most "normal" bird foods
would not provide sufficient energy quickly enough to keep a hummer going and the
only naturally ready source of such energy is the sugar in the nectar of
flowers. (Yes, flower nectar has the
very same sugar that is found in your sugar bowl). They consume at least their body weight in
sugar daily ("treats" would not be a health concern) and augment
their diets with small insects for protein. This very high rate of energy consumption has
another serious drawback - the hummer has to feed constantly to survive. However, like all birds and animals it, also,
has to sleep which it does at night but to go that long without food the hummer
could starve by morning. To avoid
starving the hummer goes into a kind of overnight hibernation called "torpor"
where the heartbeat drops from several hundred to about 30 resulting in very
little energy demand. In the morning,
with its energy load intact, the hummer takes a few minutes to "wake"
up then carries on with its daily activities.
5). Without getting
into too much scientific detail different colour is simply light with different
frequencies (red being the lowest frequency and violet the highest). Using voice as an analogy: red would be base
and violet would be soprano. Most of the
colour that we see is caused by reflection.
For example, a green tree absorbs all frequencies except green which it
reflects and we sense it with our eyes as green (assuming no colour
blindness). This reflective material is
known as pigment. Like most birds
hummers have pigment but they also have prismatic cells in some of their
feathers especially the throat area (referred to as gorgets) that break up
light (refract) into the various colours the same way that crystal chandeliers
do. The effect is that the bird glows or
looks iridescent. Thus the gorget of the
male hummer usually looks all black because it does not carry any pigment and
therefore does not reflect any light but, when he decides to "impress the
ladies" he knows the exact angle to turn his head and body so as catch
good sunlight and refract whatever colour he has been endowed with (usually
red). The females seem to approve.
There are 320 different species of
hummingbirds in the world and all are in the Americas
with about 15 or so showing up in the US
(mostly in Arizona), 5 in Canada and 2 in Saskatchewan. The common one around here is the Ruby
Throated with the odd stray Rufous. The
male Rufous is almost all copper coloured and in good sunlight shines like a
newly minted copper penny. It is very common in
the Rocky Mountains In flight the wings make a high pitched
metallic whine and several males at a feeder is quite spectacular.
Male hummers are more brightly
coloured than the females which do not have prismatic gorgets. Like egrets and swallows hummers were also
hunted for their feathers for the fashion industry just over a century
ago. Because of the prismatic nature
of a hummer's feathers they were
utilized more like jewellery. The more
colourful the bird the greater the demand and the higher the price.
Most birds raise their young as a
couple with both parents actively involved in rearing them. One notable exception is the duck family
where the hen has the sole responsibility to raise the young. Well, in that regard the female hummer is
like a hen duck - she raises the young all by herself. The male joins other males in a kind of
bachelor group and spends the summer further north. That is why males are seldom seen around town
much beyond mid summer.
This week's pictures were taken in our backyard a few
years ago. The male is at the feeder; the
female is at the Kent Bells. The male's
gorget appears black but the back feathers are an iridescent green. This is the one big advantage of the digital
camera - it captures the iridescence of the bird that a film camera never
could. To really appreciate the
iridescence log on to my website www.johnthebirder.com.
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