Baltimore Oriole Dossier

by Carl Strang

It’s time to share another of my species dossiers. This one brings together my experiences with a bird that at the moment is to be found in the tropics. Spring can’t come too soon.

Male Baltimore oriole.

Oriole, Baltimore

This bird’s song is very loud, composed of clearly defined, sharp notes, usually a bundle of several with mixed pitches. The Baltimore oriole stays near treetops in feeding, generally. They nest in residential neighborhoods and open woods, especially beside ponds, lakes and rivers. The nest is a distinctive, unusual hanging basket, usually attached to an exposed, slender branch tip over water or a road. One spring I watched part of a nest-building, the female bringing long fibers and weaving them into a bag that already had its basic form. The stroking, pulling bill movements of the bird used the new fiber to fill a space and strengthen the bag.

Even as it deteriorates in winter, a Baltimore oriole nest is a beautiful object.

3JE86. A male foraged low in a crabapple, moving fairly quickly between perches, moving 2-3 feet at a time, looking among leaves, often burying his head among them and searching. Once he dropped to the ground in pursuit of a prey that jumped to evade him.

14JE87. Adult eating mulberries at Culver fish hatchery.

7MY88. Singing at Culver.

4MY99. First migrant noted at Willowbrook. Last spring migrant observed there 27MY.

11AU99. First fall migrant noted at Willowbrook. Last one noted 24AU.

This nest is relatively visible.

17JE00. Arboretum, Joy Path. Adult male foraging in the branch tips of a bur oak where leaves are clustered. It was searching and probing into clumps of dead leaves. It caught an adult moth, removed the wings, then flew straight to its nest overhanging the path at least 20 feet up. The moth was fairly large and heavy bodied, perhaps a noctuid. The nest is within a clump of leaves so that it does not appear suspended. Later, both the male and female were carrying food to the nest. When they were there, and for a few seconds after they left, a chorus of faint peepings was audible.

2JE01. Meacham Grove, east part. A female oriole led me to a nest that was so woven into the cluster of leaves at the end of a bunch of slender twigs that the nest was practically invisible.

There is a Baltimore oriole nest here, but it is well buried among the leaves.

16JE01. Newly fledged orioles still were close to the nest at the Arboretum, Heritage Trail. The nest was above a service road-trail just inside the fence separating the savanna area from Hidden Lake Forest Preserve, on the end of a descending oak branch’s lowest twigs. One of the fledglings was still perched just above the nest, the others were scattered on that branch and in nearby branches of other trees. They were essentially motionless for a long time, but very vocal, with distinctive calls: 3 quick identical notes that sounded like uninflected robin notes.

31AU02. A Baltimore oriole in full male breeding plumage, singing at Lincoln Marsh from the very top of a tall tree. Not full volume, and only little chattering phrases, but clear oriole voice tones, whistles. Sang for several minutes.

27JE08. Baltimore oriole fledglings have a call that is a rapid series of clear notes rising as on a scale.

2MY09. An oriole at Fullersburg was taking nectar from buckeye flowers.

4MY09. Mayslake. Series of photos of an oriole probing clusters of oak flowers and opening leaves.

Foraging oriole at Mayslake.

1JE09. Mayslake. Pair of Baltimore orioles mobbing a fox squirrel in the medium-sized cottonwood closest to the SE corner of May’s Lake. They gave frequent, loud, identical, slightly slurring notes but did not attack the squirrel. I found the nest at the end of the lowest branch on the east side of the tree, 15-20 feet up. The squirrel eventually jumped to another tree without finding the nest, escorted by the male oriole, and the female almost immediately returned to the nest.

Here is the female giving her alarm calls.

10JE09. The same pair of the previous entry is feeding a cowbird fledgling just outside their nest. In the brief time I watched, the female fed the cowbird once, the male fed it once and a nestling once.

Cowbirds and orioles are in the blackbird family.

Apparently this episode of nest parasitism doomed the orioles’ own young, as I never saw any oriole fledglings from that nest.

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