Verification of Unusual Sight Record
For Utah

Rec. # 2011-21


Common name:

Vaux's Swift

Scientific name: Chaetura vauxi
Date: May 9, 2011
Time: 1:30 pm
Length of time observed: 1 hr
Number: 12
Age: Adult
Sex: Unknown
Location: Little Bear River bridge on Mendon Road (600 South)
County: Cache
Latilong: 4143'08.20"N 11156'42.00"W
Elevation: 4413
Distance to bird: Varied from 100 to 2 meters
Optical equipment: Bushnell 8X42 Binoculars, Nikon D300 Camera with Nikon ED 80-200mm lens
Weather:  40F, heavy cloud cover, persistent drizzling rain
Light Conditions: Heavy overcast sky.
Description:        Size of bird: Slightly smaller than Swallows
(Description:)       Basic Shape:  Cigar shaped body with stubby non-forked tail, wings somewhat falcon shaped
(Description:)  Overall Pattern: Dirty Brown/Grey color with paler rump, also pale chin to breast. Darker mask around eyes difficult to see in flight, but visible in photos.
(Description:)            Bill Type: Difficult to see, photos show small pointed bill.
(Description:)                              
Field Marks and
Identifying Characteristics:
From the car I immediately identified them as a species in the Swift family by the rapid beating of longer looking swept-back wings. Before I got out of the car, I was curious about why Swifts would be feeding in the bottom of the valley near water because I had only been familiar with White-throated Swifts in Cache County which I had usually seen in canyons, foothills, and mountains. Once I got out of the car and raised my binoculars, I could immediately tell that this species was lacking the forked-tail and distinct black and white under markings of a White-throated Swift. I was able to tell that the underside of the Swifts I was observing was much too light and tail too straight and stubby to qualify it as a Black Swift candidate. There were a multitude of at least three species of swallows in the area, but the speed at which the Swift was moving and their over-all cigar shape set them distinctly apart from the swallows. The Swallows were generally feeding on both sides of the road over the water, while the Swifts used the wet road as a corridor through a 200 meter section of Black Willows that lined both sides of the road. They would generally turn at or before the end of the wooded area and then return feeding sporadically along the road to do the same thing at the other end of the corridor.

So I had narrowed the species candidate down to Chimney and Vaux's. I was able to get some good looks at their underside when they would turn, usually in a brief glide with wings and tail flared wide(see photos 7246 and 7247). I could tell with binoculars that they were quite pale underneath, lighter towards the front near the beak and then fading to brown past the breast. Using a National Geographic Field guide, I decided that it looked more like the Vaux's than the Chimney underneath, but because they are so similar and not having identified a Chimney Swift before, and having nothing to compare it to other than the guide itself, I still was not convinced. I proceeded to take nearly 40 photos with my Nikon D300 and a zoom telephoto lens at 200mm. I was having several challenges initially due to the speed and quick erratic turns while feeding. Then as I observed their route back and forth I got better at getting subjects in the picture. The problem then was that I couldn't get my camera to focus in the available light at the speed I had to shoot at with the willows in the background. I decided to increase my ISO so that I could shoot at higher speeds. Finally I was able to stop motion enough to get some helpful photos as long as the sky and the bird was all that was in the photo. Meanwhile I had also noticed that the rumps on the Swift's seemed to be pale, which I confirmed to be a key to identifying Vaux's from Chimney. I positioned myself on a bridge on the side of the road where the flight corridor was narrow and continued shooting photos until I finally captured a low flying Swift at an angle that shows a lighter rump set apart from the otherwise similarly colored upper parts(photo 7259).

The 12 Vaux's Swifts did not glide as often as swallows, but when they did they held their wings at a slight downward angle (photo 7248). While I was taking pictures they flew within a couple of meters of me many times. They did not fly much higher than the trees and were at times right near the ground. They seemed to be confident enough flyers that occasional cars and trucks did not bother them at all, I observed them flying within a couple of meters of traffic whether head on or coming from behind.
(see photos)
Song or call & method of delivery: None
Behavior: The Swifts used the wet road as a feeding corridor through a 200 meter section of Black Willows that lined both sides of the road. They would generally turn at or before the end of the wooded area and then return feeding sporadically along the road to do the same thing at the other end of the corridor.
Habitat: Wooded area near wetlands and Little Bear River.
Similar species and how
were they eliminated:
As described above: Fluttery, Speedy flight and over-all falcon-like winged cigar profile set it distinctly apart from swallows in the immediate area.
Vaux's Swift was:
1) Slightly smaller than all swallows in the area - different than White-throated and Black. Chimney would have been similar in size to swallows.
2) Void of distinct black and white under markings - different than White-throated.
3) Pale under chin to breast, then fading darker - different than Black.
4) Stubby tail NOT forked - different than White-throated and Black.
5) Woody habitat near river/swamp - favors Vaux's over other swifts.
6) Pale rump in contrast to otherwise consistently darker upper-parts - different then Chimney.
Previous experience with
this & similar species:
This is my first experience with Vaux's Swift. Only other Swift identified is White-throated, seen every year. Proficient experience identifying the six swallow species common to Cache County.
References consulted: National Geographic Society Field Guide to the Birds of North America.
The Audubon Society Encyclopedia of North American Birds by John K. Terres
Description from: Notes taken at time of sighting
Observer: Kurt David Kotter
Observer's address: 140 West 200 South, Mendon, Utah 84325
Observer's e-mail address: kurt.kotter@gmail.com
Other observers who independently identified this bird: My father David Kotter was with me, and collaborated with making the identification, but not independently.
 
Date prepared: May 11, 2011
Additional material: Several photographs of subjects in flight.
Additional_Comments: