Nesting season is a grueling marathon for birds

Look at that spot-chested young robin, hopping blithely across the lawn, stopping here and there as it searches for a meal. And take note of a young blue jay perched on a branch, gulping down a caterpillar brought by its father.

These two young birds are what it’s all about, the reason their parents migrated hundreds or thousands of miles or spent the long winter staying close to home. June is the month that most songbird youngsters jump out of their nests to join the big, bright world. These fledglings are the end product of all the hard work put in by their parents in the previous eight to 10 weeks.

First, a male bird must claim and hold a territory, somewhat easier for birds that don’t migrate, since they spend the winter nearby and know the real estate. Still, blue jays may engage in noisy shout fests with other jays as they get ready for nesting season. Male robins will joust with each other for a prime territory, one that provides abundant food and protection from predators for nestlings. You’ve likely seen these battles, with males bumping each other in the chest and engaging in shrieking, fast-paced chases, sometimes even tumbling to the ground in a foot lock.

Once the birds pair up, the work begins.

As the female builds the nest, she makes sure it fits her body, since she will be handling incubation duties. The female lays one egg per day, and waits until the last egg is deposited before starting to sit on them. This is a savvy strategy because it means all the chicks will hatch at about the same time and nestlings will be at similar developmental stages.

After the eggs hatch, the most dangerous period begins. Parent birds dash to and from the nest, beaks filled with insects or worms, to keep their hungry brood fed. And nestlings frequently cry out for more food. This sound and activity attracts predators, always on the lookout for a meal.

After about two weeks the youngsters leave the nest, but there’s no respite for their parents, who continue to feed their hungry youngsters for some weeks. Since fledglings are now spread around the area, mom and dad must track them down to feed them.

As the American Bird Conservancy states, in most bird species, parent birds make a profound investment in their offspring, working mutually to ensure a successful nest. Something like 90% of birds do this to greater or lesser degrees, in contrast to the mammal world, where females generally handle all parenting duties.

Once young blue jays are truly on their own, their parents’ work is done for the year. But robins rear two sets of youngsters in our short summer season, fairly unusual in the songbird world. This means that as the father bird teaches life skills to the first batch of young birds, their mother is building a second nest and getting ready to repeat the whole process. (Other two-timers during nesting season include gray catbirds and ruby-throated hummingbirds.)

This kind of exhausting schedule is necessary for species survival but is hard on individual birds. Nature is a tough grader, unforgiving of small mistakes as birds learn the ropes, and more than half of this summer’s youngsters won’t be alive for a first birthday. For those that make it through their first year, the odds of survival for several years or longer go up.

Much of this unceasing work by parent birds is invisible to us, as it should be. But it lies behind all the newly minted blue jays and robins and chickadees and all the other birds we enjoy in the fall and winter.

St. Paul resident Val Cunningham, who volunteers with bird organizations and writes about nature for local, regional and national newspapers and magazines, can be reached at valwrites@comcast.net.