June 10, 2019
Babies are everywhere around the farmyard. Bird babies of
all colors and sizes fight over who should get first use of the bathing
facilities at the little pond. Rabbit babies are living
under the deck and visit my flower garden at their
doorstep. Kestrel babies squawk constantly, complaining
they are on the verge of starvation while making so much noise it must
be extremely difficult for the harried parents to catch a mouse or
sparrow that has not been warned of their presence. Fawns are
beginning to follow their parents as they feed and can’t resist
gambling about, chasing each other. Tadpoles of all sizes line up
along the edge of the little pond, while toads and grey tree frogs
still sing and presumably continue to lay eggs. Caterpillars are
appearing, along with holes in the leaves of all sorts of plants.
Most wild babies have to grow up quickly as the great majority end up
as meals for other species, and the faster they become proficient at
moving around and caring for themselves, the more likely they are to
survive. Two weeks is a common length of time for the average songbird
to grow from a blind, naked mite to a fully feathered creature capable
of flying about (although most do depend upon their parents to teach
them how to find food for another couple of weeks). Rabbits can care
for themselves by the time they are a few weeks old and a little brown
bat can fly when only 18 days old.
If a species is going to sustain itself, each breeding female must
replace herself with another breeding female before she dies. (The
survival of any one male is less significant as most take many mates
during their lifetimes.) The numbers are amazing. Take American robins
as an instance. In order for robins to continue to arrive each spring
and nest in our apple trees, each pair will have two or sometimes three
broods each year. Each brood contains three to five eggs, so a female
could produce from six to fifteen young each year and therefore up to
thirty babies in the two years she usually lives, and considerably more
should she survive longer. If she and her mate only need to replace
themselves, what happens to all those extra offspring?
A coyote pair has an average of six young each year, although it may be
as few as two and as many as a dozen. They can expect to live 6-8
years, according to the DNR statistics, and if so, will probably have
had at least 30 pups and possibly as many as a hundred.
Consider the cottontail: a female that survives long enough to leave
its nest can expect to live about a year, although some have been known
to live four or five years. She will have three or four litters each
year with three to eight young per litter, although a few up to l0 have
been reported. Therefore, she would probably have had at least 25 young
and possibly many more. Farther south, cottontails may breed year round
with as many as 7 litters a year. We should be overrun!
The female Monarch butterfly lays about 400 eggs during her six or
eight months of life, and it has been estimated that our common toad
produces close to 5000 eggs. It is not known how long these amphibians
live in the wild laying long strings of eggs each spring and filling
many a puddle and pond with their tadpoles, but they have been known to
subsist for more than 30 years in captivity.
One of the most prolific breeders of all the mammals is the meadow
vole, a small, common rodent that lives in grassy fields and marshes
and is a close relative of our deer mouse and that pesky house mouse.
It is a short stubby rodent with a rounded face, small eyes, short fur,
and a very short tail. There are 4 species of voles in Wisconsin but
only the meadow vole occurs in any numbers. It lives above ground,
creating little round tunnels in grassy vegetation and eating foliage
and seeds and sometimes tender tree bark, and can cause severe damage,
especially during winter when it is active under the snow.
Female voles can have 10 litters per year if conditions are favorable,
and if one assumes an average litter contains six offspring, the
numbers are staggering. Voles are born naked and blind but they are
fully furred after 10 days, and reach sexual maturity at 5-7 weeks. The
arithmetic becomes complicated, but if a single female bears litters of
six babies in March and April and her female pups begin their own
litters just two months after birth that would then reach breeding age
in another two months, by the end of the season her total offspring
could top 1000 new rodents.
Some of these various babies are killed in accidents and a fair
percentage are struck down by disease, but the great majority become
part of the wild food chain. They are preyed upon by hawks, owls,
foxes, domestic cats and dogs, snakes, crows, herons, shrews, skunks,
bullfrogs, snapping turtles, largemouth bass, and raccoons.
Nature can be cruel to an individual, but the ultimate goal is survival
of each species, and barring major problems this usually is
accomplished, and the babies are certainly cute.