McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Grasshopper Sparrow / Bruant sauterelle (Ammodramus savannarum)

 Seasonal status at MBO:

JAN
       
FEB
       
MAR
       
APR
       
MAY
       
JUN
       
JUL
       
AUG
       
SEP
       
OCT
       
NOV
       
DEC
       
  common
  fairly common
  uncommon
  rare
  occasional
  no records
 
QUICK TIPS:
1) Look at the upper breast - it is distinctly streaked on juveniles and may be retained by some HY birds through fall, while it is unmarked on AHY/ASY birds and on HY/SY birds that have completed their preformative (first prebasic) molt

2) Check the secondaries - on some HY/SY birds a few central secondaries (among s4-s6) are paler and more worn than adjacent feathers, but on many (perhaps most) HY/SY birds all secondaries have been replaced and they are indistinguishable from AHY/ASY birds with uniformly worn and relatively fresh secondaries

Note that since the preformative molt can be complete, ageing beyond U/AHY is only rarely possible for this species

Ageing and sexing guidelines:

January - July:

AHY - U
Secondaries uniform in colour and wear
 
SY - U
One to three central secondaries older and paler (only very rarely still unreplaced by spring)
     

-

June - December:

U - U
Secondaries uniform in colour and wear; breast unstreaked
   
HY - U
One to three central secondaries older and paler; breast may retain juvenile streaking
   
JUV - U
Finely streaked breast
 
 
Ageing and sexing details:
 

after-hatch-year unknown

Overall body plumage in spring is not useful for ageing Grasshopper Sparrows.  Occasionally the presence of a distinct molt pattern on the wing may allow an individual to be identified as second-year, but the vast majority have to be left as after-hatch-year.


Photo by Dave Rintoul, 2004


Almost all Grasshopper Sparrows are recorded as after-hatch-year in spring because the preformative molt is often complete, resulting in second-year and after-second-year birds appearing identical.  Only the central secondaries (s4-s6) are known to occasionally be retained - examine the wing to see whether these are older and more worn than the adjacent feathers.  Note the variation, however, in the three photos below, of known second-year, third-year, and fourth-year birds respectively.  The primary coverts on the second-year bird appear distinctly narrower and more worn than on the older birds, but this is NOT considered a reliable feature, as these feathers would normally be replaced in fall, regardless of age.


Photos by Dave Rintoul, 2004


RETURN TO AGE/SEX OVERVIEW

 

second-year unknown



RETURN TO AGE/SEX OVERVIEW

 

unknown age, unknown sex

Grasshopper Sparrows lacking streaking on the upper breast may either be AHY, or else HY birds that have already completed their molt.  As such, an individuals with a plain breast offers no obvious clues to age, though in some cases the wing may help.


Photo by Dave Rintoul, 2004
 


If there is no contrast in wear among the secondaries, age is considered unknown, as many HY birds undergo a complete preformative molt and are thereafter indistinguishable from AHY birds.
 


RETURN TO AGE/SEX OVERVIEW

hatch-year unknown

Some HY Grasshopper Sparrows are readily aged by the retention of juvenile streaking on the breast, but the absence of such streaking does not mean it is an AHY bird, as HY birds acquire a plain breast during their preformative molt.


Photo by Dave Rintoul, 2004
 


Some HY birds retain up to three central secondaries (among s4-s6) after their preformative molt, and the contrast between these and the adjacent fresher replaced secondaries is indicative of HY.  However, the vast majority of HY individuals are believed to replace all secondaries during their preformative molt, and for those, there is no way to tell them apart from AHY birds by plumage.


RETURN TO AGE/SEX OVERVIEW
 

juvenile unknown

Juvenile Grasshopper Sparrows are marked with fine but distinct streaking on the upper breast.


Photo by Dave Rintoul, 2005
 


As juveniles, the wing provides few useful identification cues for this species.  Note, however, the narrow median crown stripe, which is useful in distinguishing this species from other sparrows.


Photo by Dave Rintoul, 2005


RETURN TO AGE/SEX OVERVIEW

 

2002- The Migration Research Foundation Inc.