When:

Who:

Where:

County:

Location:

Exact Site:
Hog Island Rd. at eBird hotspot pin across from UPS packing facility on the south side of the airport.

Details: (To view more text, grab the lower-right corner of a field to widen or lengthen the box)

For older records, view original documentation here.

How Many:

Age/Plumage/Sex:
adult, sex indeterminate, but probably a male

Habitat:
flying over the Delaware River

Distance from bird:
~30 meters at its closest approach, increasing to several hundred meters before it was lost and out of view

Viewing Conditions:
overcast with intermittent periods of rain. The bird was seen clearly in our optics, but colors that would ordinarily "pop" were more subdued due to the low light.

Optics Used:
Vortex Razor 10x42 binoculars, Swarovski 10x42 binoculars, Leica spotting scope

Description:
groups of Tree Swallows were moving west along the river with some consistency, and we were carefully looking through them for a rarity, such as a Cave Swallow or a rare sub-tropical Martin species. A group of approximately 25 Tree Swallows approached our position from the south (New Jersey) side of the river, flying in a northwesterly direction toward our position. As the group approached more closely, I picked up an individual that stood out by its relative size and flight behavior from the other Tree Swallows in the group. I noticed a bird that appeared to be ever-so-slightly smaller than the nearby Trees, with slightly more slender wings and "snappier" and more hurried wingbeats, creating an overall more "erratic" flight style. The bird was at a distance and poorly lit initially, and due to the characteristics noted above, I assumed it was going to be a late Bank Swallow. As the bird approached our position, I saw it bank, revealing a topside view of the bird, where I was immediately able to note that it had a clean white underside contrasting with a dark (greenish/blue) upper side with conspicuous white "wheel wells" at the sides of the rump with a clearly demarcated vertical stripe of dark feathering coloration through the middle of the rump. The white sides to the rump were very obvious, and I immediately called out "this bird has a white rump, get on it" to Jason, to imply that it could be a Violet-green, though still wanting some better views while not impulsively calling out Violet-green, though I strongly suspected it was this species upon initial observation. Both Jason and I watched the swallow approach our position more closely and the bird banked again, revealing a very pale (white) face, starkly contrasting with the rest of the upper side of the bird. I immediately called out, "Violet-green Swallow" and worked to try and get my camera ready for photos. After thinking initially that I didn't get any that showed the bird in the frame, I did get a photo with the bird, but it is not identifiable to species and would not be helpful in the committee's review of this record. Description of the bird: clearly a swallow, with an immaculately white underside uninterrupted with any other noticeable plumage features. Underwings were dark, and when the dorsal side of the bird was observable, I was able to note the conspicuous, large and clean white rump patches on the side of the bird's rump, which were separated by a thin vertical margin of dark coloration, preventing the two white rump patches from connecting with each other. Tail was dark and slightly forked (as Tree also are). Back coloration appeared slightly brighter greenish/blue than the nearby Tree Swallows, but the lighting conditions prevented this feature from really standing out. The bird had a uniformly dark upper side through to the head, where the bird showed clean, conspicuous white cheek patches, with white both above and below the eye. Bird was overall similar in size to Tree Swallow, though noticeably, but only slightly smaller.

Behavior:
typical swallow behavior--foraging over (and possibly migrating) over the Delaware River with the group of Tree Swallows. It's worth noting that, perhaps due to the strange weather conditions (a tropical storm), the swallows both in this group and through

Separation from similar species:
Tree Swallow: Tree Swallows can show variable amounts of white on the sides of the rump, to include some white, or no white at all. None show white patches along the side of the rump that are as extensive, bold and conspicuous as this individual. Tree Swallows never show white rump patches that are so conspicuous that they may cause, at a glance, the bird's rump to be entirely white. Tree Swallows can show some pale in the face, though none show the extent of white especially a bit above the eye as well as a substantial amount of white below the eye, as Violet-green do. Mangrove Swallow: think of Mangrove Swallow as a white-rumped Tree--dark navy above, with little to no white in the face, clearly demarcated with a clean white underside and a full, large white rump patch on the dorsal side of the bird. The bird in question did not have a complete white rump patch, still showing a vertical margin of dark feathering (dark blueish/purple) and significant white in the face. Currently, the United States has only a small handful of records of Mangrove Swallow, and none outside the state of Florida.

Discussion:
I believe the bird was probably an adult male, but the overcast conditions, combined with viewing the bird mostly against dark gray overcast sky prevented the observation of any vivid colors on the bird, beyond the "blacks" and "whites". While the rump patches/wheel wells, as well as the extent of white in the face were obvious in contrast to the dark coloration around the rest of the bird, it would have been quite difficult to note the vibrant green and purple on the bird's dorsal side in the lighting/viewing conditions as they were. Both Jason and I have extensive experience with Violet-green Swallow, Mangrove Swallow and any other far-flung, distant possibilities. I saw Violet-green Swallows nearly daily in Montana when I worked and lived there, often in direct comparison with nearby Tree Swallows, the same as the experience with this observation when both species were present together. I'm not sure what, if any, effect Tropical Storm Zeta had on the occurrence of the Violet-green Swallow, though I would guess there would be some correlation.

How positive are you about the identification:
Yes. I have much experience with both Violet-green Swallows and the other swallows that this species could have possibly been confused with, Tree Swallow and Mangrove Swallow.

References:

During the observation:
none

After the observation:
none

Media: