English and Scientific names:

Tundra Swan (Cygnus columbianus)

Number of individuals: 

(1 adult and 1 juvenile)

Locality: LOUISIANA: 

East Carroll

Specific Locality:

jct. of Delta Rd. x Levee Rd., s. end of Gassoway Lake, Millikin

Date(s) when observed:

25 January 2009

Time(s) of day when observed:  

8:50-9:00 AM CST

Reporting observer and address:

Justin Bosler

Lancaster, PA 17601

Other observers accompanying reporter who also identified the bird(s):

Devin Bosler

Other observers who independently identified the bird(s)

None

Light conditions (position of bird in relation to shade and to direction and amount of light):

Fairly bright, overcast skies with low ceiling.  No backlighting or glare to impede viewing conditions.

Optical equipment: 

Zeiss Victory FL 8x42 binocular (good) and Kowa Prominar TSN-4 77mm spotting scope w/ 20-60x zoom eyepiece (good).

Distance to bird(s): 

100 meters at closest point (not observed when overhead)

Duration of observation:

approx. 2-3 minutes

Habitat: 

Semi-wooded Mississippi River bottomland adjacent to vast agricultural fields.  Numerous oxbow lakes and backwaters within the Mississippi River levee system.

Behavior of bird: 

Both swans were observed flying in tandem at low altitude from S to N along the levee and over Gassoway Lake as viewed from top of levee (~1 minute after initial observation from woods at base of levee).  After a minute or so they banked toward the east and eventually dropped out of view behind some distant trees, presumably crossing into Issaquena County, MS.

Description:

Two large, white to whitish swans that appeared relatively short-necked and long-tailed.  Adult-plumaged swan had an entirely black bill, however, the lores were not seen well enough to assess coloration.  The bill did not appear oversized in relation to the head.  The forehead was rounded and sloped sharply at the base of the bill.  The neck appeared pinched-in toward the head and was held parallel to the body. First-cycle swan was largely white below with a smudgy, pale gray or brown cast to upperparts.  Head, neck, upper back, and upperwing coverts retaining pale brownish/grayish juvenal plumage, but most noticeably on the head and neck, which were more dingy gray.  The bill was dusky-pink throughout.  The flight style was almost goose-like with steady and graceful, less laborious, wingbeats.  Also, neither swan was marked with a neck collar or wing tag. 

Voice:

Silent.

Similar species:

Mute Swan (MUSW) was easily eliminated by head shape, bill shape, and lack of any orange on the bill (pertaining to adult), in addition to slimmer size, narrower wings, longer tail, etc.  Immature MUSW can be eliminated by the predominantly whitish plumage and paler (dusky-pink) bill base. 

 

Trumpeter Swan (TRUS) can be eliminated by slimmer structure of body and wings, relatively short and tapered neck, longish tail, rounded, sloping head, bill with concave sides, and dark eyes appearing isolated on face. In flight, neck appeared thinner and narrowed at the head, unlike TRUS. Flight style was more fluid than seen in TRUS with snappier wing beats. Unfortunately voice could not be used to further eliminate TRUS.

 

Advanced stage of molt of immature perhaps of greatest significance in eliminating TRUS. Considering cygnets stay with their parent(s) through their first year supports the fact that the immature swan is less than a year old and in its first molt-cycle. The molt timing of immature TUSW is significantly different from TRUS in that it occurs within a much shorter period of time. That said, one can safely eliminate immature TRUS in mid-winter by carefully noting plumage aspect. A mostly white body (especially back and rump) and remiges in Jan is essentially diagnostic for TUSW in their first winter, whereas TRUS would be largely gray-brown throughout, including back and rump, with only scattered white feathers.

Photographs or tape recordings obtained?

No photos obtained.

Previous experience with this species: 

Rather extensive field experience with Tundra Swan in the mid-Atlantic states fall through spring. Somewhat limited experience with Trumpeter Swan from MN, NY, and PA, with those few encounters involving individuals or small family groups, and not in direct comparison with Tundra.

Identification aids:

after observation: Frontiers of Bird ID listserv discussion

This description is written from: 

notes made during observation and memory.

Are you positive of your identification? If not, explain: 

 

Yes, 100% positive.

Date and time: 

11 March 2009    11:30 PM