Differing Nesting Strategies

     Last evening I saw a flurry of wing flapping on the next-door neighbors' garage roof.  Looking closely, I saw the fluttering was caused by a parent mourning dove feeding its two recently-fledged young.  I remembered seeing a pair of young doves early last month and that reminded me that a pair of mourning doves, like most of their clan, produce two young a month, on average.  And because they start nesting here in the Middle Atlantic States in March and continue into September, a pair of mourning doves can produce six broods for a total of twelve offspring a year.  But not all chicks reach maturity because of eggs falling through flimsy nests in trees, crows, raccoons, opossums and other kinds of predators eating eggs and young, and Cooper's hawk preying on adults.  Still, mourning doves are abundant in North America.  And so are Canada geese in the Lower 48 of the United States, even though both species are game birds, hunted by humans in autumn.
     Canada geese traditionally nest in Canada, but populations of them are common across much of the Lower 48 because of stocking for hunting.  Mourning doves and Canada geese are abundant game birds in the farmland of the Mid-Atlantic States where they eat grain and green shoots respectively.  Both species are major parts of that human-made habitat the year around.
     But the most interesting part of the life histories of these game birds is the reproductive strategies they evolved over millions of years, both of which are different from each other but, obviously, successful.  Each female mourning dove lays two eggs each month, for six months, alternately in two tree nests while each female Canada goose lays one clutch of four to six eggs each year in a grassy cradle on the ground.  And both parents of the two species care for their young until they are old enough to take care of themselves.  Each pair of geese, by the way, get away with only a small number of goslings a year because goose parents are large and fiercely protect their progeny.  The goslings, therefore, have a low mortality rate, even though they live on the ground and on bodies of water.
     Young doves are born helpless and need to be fed a combination of regurgitated throat phlem and predigested seeds until they fledge their nurseries, and a short time after fledging.  Young geese, however, hatch covered with fuzz, with their eyes open, and ready to feed themselves on a variety of aquatic and land vegetation within 24 hours of hatching.
     The goose way of raising young is straight-forward; one clutch per year.  All the goslings hatch on the same day and all grow at the same rate until independent by late summer.  But the doves' way of rearing offspring is more complicated.
     Mourning doves in the Middle Atlantic States start to raise chicks in March.  Then the female of each pair lays two eggs in a sloppy nursery she built on a tree limb, or in another bird's cradle.  When those first two chicks are half-grown, their mother lays two eggs in another nest and the parents take turns incubating the eggs and small young.  The parent not incubating ingests grain and seeds and feeds the offspring.  About the time the first young leave their nursery, the second pair of babies hatches and is brooded and fed by each parent in turn.  And when the second brood is half-grown, their mother lays a third clutch of eggs in the first, now empty, nest.  And so it goes all summer into September, resulting in about six broods a year.
     Mourning doves and Canada geese have different ways of rearing young, but each way is successful, as are all the various ways that successful animals raise offspring.  Nature is forever experimenting with different ways of surviving in the seemingly unending variety of niches on Earth. That is one of the many reasons why nature is always beautiful and intriguing to experience everywhere and at all times.