Species Spotlight: Bobolink
Common name: Bobolink
Latin name: Dolichonyx oryzivorus
Status under SARA: SARA listed the Bobolink as “eligible for listing”. COSEWIC assessed this species as threatened in 2010.
Range: Originally found in tall-grass prairies and meadows, over the last century the Bobolink has adapted to farm croplands, such as hayfields and pastures. They can be found in southern Canada during their breeding season and have an extensive migratory pattern to South America.
Life span: 2-9 years and on average 5 years in the wild.
Size: Females and males are similar in size. Their wingspan is 25-30cm, weighing 29-56g (average 40-45g) and their head-to-foot length is 15-21cm.
Population estimate: Global population estimated at 8 million but with only ¼ of that breeding in Canadian habitats. The last assessment was in 2008, concluding a decreasing trend in population over the last 4 decades.
The Bobolink’s common name originates from a poem written by William Cullen Bryant back in the late 19th century. William wrote about a bird he then called Robert of Lincoln. This name was shorten to Bob of Lincoln, and finally became the name it has today: Bob o’Link. The poem was written on account of the bird’s striking appearance. During the breeding season, the male Bobolink looks like it is wearing a reversed tuxedo with a striking yellow cap. The male has black under parts and wings with 3 large white stripes and smaller stripes of browns and yellows. Females have more of a finch-like look with a black and yellow striped body and a pale yellow belly. In non breeding season, the males also share this similar colouration.
The Bobolink’s habitat is greatly dependent on food resources. The species name Oryzivorus is Latin for “rice eater” since their diet comprises of rice, oat seeds and other grains. This is due to the Bobolink’s vital need to accumulate energy from fat reserves for the extensive migration to South America. They also feed on invertebrates including insects, arachnids, and larvae as protein sources, especially when foraging for their growing hatchlings. You can find these birds foraging all day in large open fields of tall grasses, prairies and meadows, or in freshwater marshes and coastal areas.
The Bobolink has the longest migration of all North American songbirds, flying 20,000km from mid-Argentina to mid-Canada. The birds have iron oxides in their beak bristles that help orient them with the earth’s magnetic fields to direct their path each migration!
Upon arrival in the springtime, males begin courting females by singing and dancing, and the females choose a mate after they build their nests. The Bobolink’s song is very distinct and is sung almost constantly throughout the day. Unlike many other songbirds, Bobolinks build their nests on the ground. Females find the perfect spot to dig a little cup-like depression in the soil and then patch it up will a collection of grass and stems. Bobolinks are polyandrous, which means that females will mate with multiple partners resulting in a clutch of eggs with a varying genetic make-up. This type of reproductive strategy is the opposite of ‘putting all the eggs in one basket’; having multiple fathers ensures that at least one of the eggs will have strong enough genes to survive.
Females can lay 3-7 eggs which she will incubate for 11-14 days. The eggs are quite colourful – they can be bluish-gray to reddish-brown speckled with dark purples spots. Bobolinks have cooperative breeding meaning that other non-breeding bobolinks will help out with gathering food for the altricial hatchlings.
The increase of agriculture – especially the development of grass varieties that can be harvested multiple times per season – has had a negative impact on the Bobolink population. Bobolink nests get destroyed by tractors during mowing since they are hidden at ground level. Eggs are destroyed this way, or by related nest abandonment, and hatchlings can also be killed in more advanced nests. For this reason, Bobolinks now have to travel to find untouched or fallow grasslands, which is not an easy task with continual habitat loss to large-scale farming.
The Bobolinks also have difficulties in their wintering grounds. The same farming issues occur in South America and the Bobolink can be perceived as an agricultural pest. They are also exposed to the pesticides used in agriculture while foraging for food.
What’s Being Done
The Bobolink has been protected under the Migratory Bird Convention Act since 1994 and multiple provincial Wildlife Acts. At the global level, this species is listed as secure and least concern but at regional levels, Bobolinks are threatened and under monitoring projects such as the North American Breeding Bird Survey, Ontario Breeding Bird Atlas, Atlas of Breeding Birds in Alberta, and Éudes des Populations des Oiseaux du Québec.
Recovery goals include research on the Bobolink’s habitat and reproductive behaviour due to ongoing changes and linking conservation efforts with agricultural management.
What Can You Do?
Volunteering for bird surveys and sightings is a great way to help out wildlife. It allows conservation groups to map out where the species are located in order to best accommodate their recovery goals. Find out how to become a volunteer in your area here.
For farm land owners, they can read up on bird-friendly managing methods to not only help out the bobolinks but all other grassland wildlife. For example, check out this brochure with The Couchiching Conservancy!
You can sign up for helping out different conservation campaigns and continue giving awareness about wildlife and what we need to do to conserve nature! Check out the events Nature Canada has based solely on raising awareness about birds here.
Thank you to guest blogger Tina-Louise Rossit for contributing this species spotlight.