Verification of Unusual Sight Record
For Utah

Rec. # O-2020-01

Common name:

Baltimore Oriole x Bullock's Oriole hybrid

Scientific name: Icterus galbula
Date: 6-12-2020
Time: 7:30am
Length of time observed: Off and on for over an hour
Number: 1
Age: adult
Sex: Female
Location: Tracy Aviary's Jordan River Nature Center
County: Salt Lake
Latilong: 40.69387125 -111.92218378
Elevation: 4300ft
Distance to bird: 10m at closest
Optical equipment: 10x50 Nikon Binos, Canon SX50 Digital Camera
Weather: Mostly sunny,calm and 70F
Light Conditions: good
Description:        Size of bird: Medium sized passerine
(Description:)       Basic Shape: passerine
(Description:)  Overall Pattern: overall uniformly bright yellow-orange
(Description:)            Bill Type:  
Field Marks and
Identifying Characteristics:
We had just finished a practice bird survey and were discussing the results, when Tim, John and I spotted an Oriole foraging in an Elm nearby. Naked eye it was very bright yellow-orange so I assumed a male Bullock's, but when we put the binos on it we all noticed it had no black markings on the throat like a male Bullocks. We then watched it for some time as it repeatedly visited and feed young in a nest. Uniformly bright yellow orange on the torso and face, including the belly and flanks, it had 2 white wing bars, a long slightly decurved silver bill, some smudgy black markings on the crown, nape and back and a faint eyeline. There were a couple Bullocks Oriole's nearby but they did not interact with this bird and no male was seen visiting the nest.
(see photos)

** This record was withdrawn from consideration as a Baltimore Oriole.
The following comments were influential in concluding that this bird was most likely a hybrid:

Cameron Cox: "The single most reliable trait for females is where is the yellow/orange brightest. In female Baltimore its on the chest, in Bullock's it is in the malar area. In this bird it appears the bright orange malar connects to the bright orange chest which leads to the conclusion that it is a hybrid. The wing coverts also have much more white in them than I would be comfortable for in a Baltimore. I've seen a couple of similar birds on the Gulf coast of Texas and have probably passed off others, for as Bryant mentioned, this isn't the typical appearance of a hybrid and at first glance is very BAOR like. "Typical" for this hybrid pair is very much a moving target though. One of the times when I've been in the hybrid zone in eastern Colorado I remember seeing five birds in a row, all hybrids, all quite different. In appearance they seem to function as a hybrid swarm though hybrids are less fit than either parent species as they oddly inherit the molt strategies of both parents and end up doing two prebasic molts pre year."

Mark Stakehouse: "Since this record is no longer before the committee, I can comment that yes, this appears to be a hybrid. Even though the characteristics of female hybrids are not well understood/established, there are a number of characters that are intermediate in this individual. The just posted photo from Julie Frost provides even better evidence of a hybrid.

As Cameron notes, the bright orange of the head and breast looks like it can't make up its mind what it's doing. You can see in Julie's photo that it's quite patchy and variable, that actually isn't good for either parent species. The eyeline is too well-defined and dark for a pure female BAOR, and the supercilium too prominent as well. You can see in Julie's photo that there are black feathers scattered in the throat. I also agree with Cameron that the edgings of the coverts are whiter than typical for BAOR, making a less-defined wing-bar that is more like BUOR.

The fact that it is apparently nesting, presumably with a BUOR mate, so far west of the contact zone, is also suspicious, and perhaps unlikely for a vagrant pure BAOR."

Song or call & method of delivery: Heard giving a chatter call, faster and not as scratchy as a Bullocks. Also a clear single whistle
Behavior: Actively foraging, including fly catching, then delivering food to chicks in a nest
Habitat: Riparian cooridor of Jordan River, foraging in tall cottonwoods and elms
Similar species and how
were they eliminated:
Bullock's Oriole-Males have a black throat,back,nape and crown, and bold white wing patches. Even 1st year males have a black throat. Females are very dull with a pale gray belly and back, the yellow is restricted to the head and tail and is very dull olive-brownish yellow, not bright or orangish. Direct comparison with both sexes. Chatter call of Bullock's different and noted in the field, Bullocks is slower and scratchy, more striking, Chatter call from this bird was faster and less harsh and more subtle.

Hybrid Bullock's X Baltimore was harder to rule out, very few references or photos of female hybrids, but Steven Mlodinow has some photos on eBird of some female hybrids in Colorado, and they seem to have a paler belly more like a Bullocks than this bird. Hybrids are very rare and unexpected outside hybrid zone in the western Great Plains, so would be unexpected in Utah. Hybrids should only be considered if something is wrong for a true species and this bird seems fine for a Baltimore female. Overall Baltimore greatly out numbers hybrids as a whole so a hybrid would be statistically less likely, as well as out of range. But most importantly no field marks are off for Baltimore and suggest Bullocks

Hooded Oriole, female would be more yellowish with a longer tail and bill, don't make a chatter call similar to this birds

Orchard and Scott's Oriole females very yellow, not orangish.

Streak-backed seems very unlikely, calls different as well,more harsh, female has black throat.
Previous experience with
this & similar species:
Yes, several males and females in Texas, Colombia and one female in Utah at Salt Lake International Center in October 2012
References consulted: Audubon Bird of North America app, Sibley, eBird
Description from: Notes taken at the time of the sighting
From photo(s) taken at the time of the sighting
Observer: Bryant Olsen
Observer's address: 84102
Observer's e-mail address: **
Other observers who independently identified this bird: Tim Brown, John Middleton, Linda Johnson and Angela Dean were with me, Matthew Pendelton and several other later.
Date prepared: 6-12-2020
Additional material: Photos
Additional comments: eBird checklist: