Bobolink sits on wheat

A Refuge for the Bobolink

Here at the Fauna Nature Conservancy we are privileged to have a healthy population of Bobolink return year after year to nest in our fields. Not unlike the majority of birdwatchers and wildlife photographers, I get excited anticipating the arrival of these long-distance migrants every month of May. These robin-sized songbirds travel an incredible 20,000 kilometres to and from southern South America each year; one of the longest known songbird migrations in the world. This year, we built an observation blind at the reserve in order to get a more intimate look at their nesting behaviours.

A male bobolink
Male bobolink. © Justin Taus
A rectangular wooden building with brown and green camoflauging sits in a field
Our new bobolink observation blind allows for intimate views of breeding behaviours. © Justin Taus

Bobolink: A Threatened Species

Sadly, Bobolink populations have been constantly declining over the last five decades according to data compiled through the North American Breeding Bird Survey. Populations in Eastern Canada, their core breeding range in the country, have been the most affected. It is estimated that the species’ numbers in Canada declined by 5.2% per year in the period between 1968 and 2008, adding up to an incredible 88% drop in population size over that 40 year period. The main causes of this decline are believed to be incidental mortality from agricultural practices (mowing fields while birds are nesting), habitat loss and fragmentation, and exposure to pesticides, according to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

At Fauna we’ve adapted our haying practices to ensure that Bobolinks can nest in peace throughout the months of June and July.

Brown female boblink against a green background
Female bobolink. © Justin Taus

A Busy Couple of Months

Our newly built Bobolink observation blind has proven to be a great tool and has allowed us to document the species’ nesting behaviours in detail.

In mid May, male Bobolinks are the first to arrive in their striking black, yellow and white breeding plumage. Over the following weeks, they are busy displaying, singing, fighting and chasing after one another as they passionately compete to claim their territory.

A black bobolink stands in grass, spreading his wings
A male bobolink displays near a nest site. © Justin Taus
Male bobolink spreads his wings while perched on a branch
A male bobolink spreads his wings and sings as he competes for territory. © Justin Taus

The females, recognized by their uniform brown and yellow plumage, arrive shortly after the males.

A black male bobolink and brown female boblink perch on a branch
A male (top) and female bobolink rest on the same perch.

Females then take to choosing a suitable area to build a nest on the ground within the male’s territory. The small nests, no larger than 4 inches wide and 2 inches deep, are most often placed on damp soil near the base of a plant. The female first clears away the nest site, then creates a small depression in the soil that she lines with grasses gathered from within a 100-yard radius. Building the nest takes one or two days.

Females then lay 3–7 eggs and incubate them for up to 14 days.

A bobolink stands in a field holding pieces of grass in her beak
A female bobolink lines her nest with grasses. © Justin Taus

A polygynous species, Bobolink females will mate with several males during the breeding period, meaning that any single clutch of eggs can have several different fathers.

Both parents take part in feeding the nestlings, with males helping to various degrees (depending on the amount of nests to which they must tend). Sometimes more than two adults participate in feeding the young. It is believed that this most likely occurs when there are more than one fathers in the clutch.

A black bird perches on top of a tree holding a green insect in his beak
A male bobolink with an insect for his offspring. © Justin Taus

Although unable to fly, chicks normally leave the nest after a 10 day period and hide in thick vegetation for days until their flight feathers have grown in.

Three brown bobolinks perch together
Young female bobolinks flock together in mid-July. © Justin Taus

At this point, birds from different nests group together in foraging flocks, allowing juveniles to learn to feed themselves efficiently. These foraging flocks occur for approximately a month, after which the birds finally depart the breeding grounds.

Several bobolinks perch near each other in a field
Foraging flock of juvenile bobolinks. © Justin Taus

Until Next Year!

Bobolink are present at Fauna until late July. We are already looking forward to observing and studying these magnificent birds again next year. Keep an eye out for our birdwatching dates in 2021 if you’re interested in witnessing this extraordinary spectacle.

Support the Bobolink at the Nature Conservancy!