Plate by Andy Birch

griseus

caurinus hendersoni

Acknowledgements to the dowitcher and shorebird gurus

Richard Crossley

Julian Hough

Jean Iron

Alvaro Jaramillo

Frank Pitelka

Kevin Karlson

Ken Kaufmann

Michael O’Brien

Ron Pittaway

Claudia Wilds

Ruff Sharp-

tailed

Sandpiper

Pectoral

Sandpiper

Buff-breasted

Sandpiper

Upland

Sandpiper

What is Gestalt or Jizz? How Can Birders use It?

Gestalt ~ Anthropomorphizing field marks

Humans have an innate ability to recognize each

other

Who are

these

people?

Can gestalt be used as a field mark?

Drawbacks

no single gestalt field mark is conclusive

gestalt field marks are hard to quantify

gestalt field marks can vary

Advantages

when gestalt field marks are used together, one has a powerful tool

for field ID

CAVEAT

No single field mark is fail proof

Holistic field identification is emphasized

OUTLINE FOR FIELD IDENTIFICATION

• IMPORTANCE OF GESTALT

• STRUCTURE

• ALTERNATE PLUMAGE

• BASIC PLUMAGE

• JUVENAL PLUMAGE

• DISCUSSIONS

STRUCTURE = GESTALT = GENERAL IMPRESSION

Gestalt = conservative field mark

Gestalt birding is not meant to replace looking at details

They should complement each other

Semipalmated Sandpiper Western Sandpiper

DOWITCHERS

gestalt

Long-billed Dowitcher Short-billed Dowitcher

Sep 4, 2004 – Brazoria, TX

LB Dow

Aug 6, 2005 – Bolivar, TX

SB Dow

July 31, 2005, Bolivar, TX

Left = LBDO; upper right = SHBDO

Aug 25, 2005 – Bolivar, TX

Top: L to R; LB, ShB, LB, Shb; BOTTOM: L to R, ShB, LB

AA

Long-billed Dowitcher Short-billed Dowitcher

B

0

5

10

15

20

0 5 10 15 20 25 30 35

Loral Angle (degrees)

num

ber

Long-billedShort-billed

C FIGURE 1. A and B show how loral

angle is defined using Long-billed (A)

and Short-billed (B) dowitchers as

examples. C shows a histogram of

loral angles determined from

photographs of the two dowitcher

species.

LORAL ANGLE – DIFFERENCES IN FACIAL IMPRESSION

SUMMARY OF STRUCTURAL FIELD MARKS

Long-billed Short-billed

Legs longer shorter

Supercilium straighter more arched

Loral angle smaller larger

Posterior more elongated less elongated

Posterior shape attenuated less attenuated

Bill longer, straighter shorter, more decurved at tip

Primary proj. shorter longer

Aug 11, 2005 – Bolivar, TX

SB Dow

SB Dow

Figure 3. This first-year, presumably male Long-billed Dowitcher was photographed 7 Jan

2006 at Bolivar Flats, TX. Note that although the length of the bill is on the shorter end of

the spectrum for Long-billed, it appears straighter than Short-billed. Note more acute loral

angle, straighter supercilium, dark chest and sides, barred (rather than chevroned) flanks),

and dark upperparts. Some juvenal scapulars are still present.

LB Dow

LB Dows

OTHER CONSERVATIVE FIELD MARKS

TAIL PATTERN

Cin-Ty Lee

SB Dow

LB Dow

TAIL PATTERN SCHEMATIC

Short-billed Long-billed

2. ALTERNATE PLUMAGE

Usually attained in full by mid- to late April

(molt begins on wintering grounds)

Southward migration occurs in alternate plumage

Main molt takes place on wintering grounds

But LBDO undergoes partial molt during migration

Spring birds are in fresh alternate (or transitioning into alternate)

Summer/fall birds are in worn alternate

(except for 1st summer birds)

Figure 9. A) Long-billed Dowitcher in fresh-alternate plumage at Anahuac National Wildlife Refuge,

TX in mid-April 2002. Note the squared off white feather tips on the median and greater coverts.

Note also the black-barred sides of the breast and the diagnostic white edges to the black bars

(these will be worn away by mid summer). Note also that the primaries do not project beyond the

longest tertial. In this bird, black stripes on tail feathers distinctly thicker than white stripes. B) Long-

billed Dowitcher in fresh alternate plumage photographed in spring in Japan, showing small loral

angle, short primary projection, and long and straight bill, barred sides. Squared off white feather tips

give this bird an overall white-barred appearance from a distance. Photo A by Lee and B by

Yamamoto.

A B

caurinus

hendersoni

griseus

Long-billed Dowitcher

Short-billed Dowitcher

A B C

D E F G

Alternate Greater Covert Feathers

C-T Lee

Figure 7. Fresh (A, B) alternate greater covert feathers in Long-billed. Worn Long-billed covert in C.

Variations in fresh covert feathers in Short-billed (D-F) along with worn covert feather (G).

LB Dows SB Dows

SB Dow

LB Dow

Top – Long-billed Dowitcher, Bottom – Short-billed Dowitcher

Top: LBDO (early April, bolivar); bottom LBDO

July 31, 2005, Bolivar, TX

Left = LBDO; upper right = SHBDO

Aug 25, 2005 – Bolivar, TX

Top: L to R; LB, ShB, LB, Shb; BOTTOM: L to R, ShB, LB

30 July 2006 – Ventura, CA

SHBDO

SUMMARY OF ALTERNATE PLUMAGE

FIELD MARKS

Long-billed Short-billed

Covert feathers flat white tips V-shaped white tips

Flanks vertical bars fringed white bars or spots

2. BASIC PLUMAGE

Usually attained in full by early September

(although vestiges of juvenal plumage persist well into fall)

Beware of first summer birds

Short-billed Long-billed

Short-billed Dowitcher

Aug 11, 2004 – San Diego, CA

Pale, contrasting throat

Scalloped/spotted sides which are lighter than neck

Pale chin, but less contrasting

Barred sides which are same color as neck

LB Dow

Short-billed Dowitcher, Wexford,

Lady's Island 8th July 2004 © Tom

Shevlin

Short-Billed Dowitcher, Azores,

Cabo da Praia 14/12/03 © Martin

Oomen

SB Dows - vagrants in Europe

23 Nov 2006, Pelican Island, TX

Ted Eubanks

Long-billed Dowitcher

19 Nov, 2005

Bolivar, TX

LBDOs

Aug, 2005

Bolivar, TX

SB Dow

LB Dows

Short-billed Dowitchers

3. JUVENAL PLUMAGE

Short-billed Long-billed

Long-billed Dowitcher,

Cornwall, Drift reservoir 23

Sept 2005 © Mike Barker

Canon 20D 1/320 @ f5.6

Long-billed Dowitcher,

Cornwall, Drift Res.

25/09/05 © Andy Cook

Sep 4, 2005, Bolivar, TX ShbDo