locations of these sites differed. The Sharp-tailed Sparrow prefers the
higher and therefore dryer portions of the marsh where black grass is
the characteristic plant. Contrastingly the Seaside Sparrow almost
always chooses the wetter portions of the marsh (Cruickshank, 1942:45;
Forbush and May, 1939:514; Stone, 1937:906; personal observations)
where several species of plants are abundant. In areas that have been
ditched, as have almost all marshes in New Jersey, the mound of
excavated muck is ideal for the growth of marsh-elder. Rows of these
bushes are present on many of the marshes of New Jersey (pl. 3, fig.
a). The location of four of the eight Seaside Sparrow nests in these
"hedgerows" indicates that they provide suitable, if not preferred,
sites for the species.
EGGS AND INCUBATION
I found no nests of either species before they contained a complete
complement of eggs and therefore was unable to ascertain the incubation
period for these species. Brood patches were evident on female
Sharp-tailed Sparrows by June 1, probably indicating that laying began
near this date. Cruickshank (1942:456) lists egg dates of the
Sharp-tailed Sparrow as concentrated in early June, with extremes of
May 19 and August 4. He thinks the species probably has two broods. For
the Seaside Sparrow, Cruickshank (1942:458) states there is probably
but one brood and that egg dates are concentrated in early June, with
extremes May 23 and July 2. Stone (1937:907, 911) considers four eggs a
normal clutch for both species, but cites instances where three and
five eggs were thought to be complete sets. Four of the eight Seaside
Sparrow nests I found contained at least three eggs, and four contained
at least four eggs. Four of the five Sharp-tailed Sparrow nests I found
contained at least three eggs and one contained four eggs.
Female Seaside Sparrows do all of the incubation. The male, while the
female is on the nest, remains a short distance away. He sings often
and gives alarm notes when there is a local disturbance. These chipping
notes bring the female off the nest, and then they both chip at the
intruder. The male accompanies the female to the feeding grounds and
normally they return together.
As previously mentioned, male Sharp-tailed Sparrows take no part in the
nesting activities.
YOUNG
I studied growth and changes in behavior of the young. Since I could
see no behavioral differences between the nestlings of the two species,
this subject will be discussed jointly for the two forms.
_Growth_
The color of the natal downs of both species is similar. Dwight
(1900:190), who saw newly hatched nestlings only of the Sharp-tailed
Sparrow, described the color as grayish wood-brown. A series of white
neossoptiles is present at the posterior end of the ventral tract in
both species. These feathers are more numerous in the Seaside Sparrow.
Dwight (1900:98) saw no neossoptiles on the underparts of any of the
passerines he examined. Seaside Sparrows have a mid-dorsal row of downs
in the dorsal tract near the uropygium. These feathers are lacking in
the Sharp-tailed Sparrow and constitute the major difference, in this
plumage, between the two species. The neossoptiles of three Seaside
Sparrows and one Sharp-tailed Sparrow were counted. These counts were
checked on the young birds studied in the field. The number and
placement of these feathers appear in plate five. There appears to be a
consistently greater number of natal downs in Seaside Sparrows, when
compared with Sharp-tailed Sparrows.
TABLE 1--DAILY WEIGHT IN GRAMS OF NESTLING SEASIDE SPARROWS AND
SHARP-TAILED SPARROWS FROM LAVALLETTE, OCEAN CO., NEW JERSEY.
======+================================================================+
Day | _Ammospiza maritima_ | Average |
------+---------+------+---------+------+------+------+------+---------+
0 | ... | 2.2 | 2.3 | ... | ... | 2.2 | 1.8 | 2.1 |
1 | 3.0 | 3.3 | 3.5 | 3.7 | 3.3 | 2.6 | 2.1 | 3.1 |
2 | 4.6 | 5.0 | 5.2 | 5.0 | 4.8 | 3.7 | 3.0 | 4.5 |
3 | 7.0 | 5.5 | 7.2 | 6.9 | 6.9 | 5.9 | 4.7 | 6.3 |
4 | 9.4 | 8.1 | 10.6 | 9.1 | 9.1 | 7.6 | 6.4 | 8.6 |
5 | 12.5 | 11.1 | 12.3 | 11.4 | 11.1 | 9.9 | 8.7 | 11.0 |
6 | 14.6 | 13.1 | [1]11.1 | 13.9 | 13.7 | 12.6 | 9.6 | 13.0 |
7 | [1]11.6 | 13.9 | 12.1 | 15.1 | 14.8 | 14.3 | 11.8 | 13.7 |
8 | 14.9 | 15.5 | 13.4 | 14.9 | 14.8 | 14.6 | 12.4 | 14.4 |
9 | 15.2 | 15.8 | 13.8 | 16.2 | 16.1 | 16.0 | 14.4 | 15.4 |
10 | ... | ... | ... | ... | 15.9 | 15.5 | 14.3 | 15.2 |
------+---------+------+---------+------+------+------+------+---------+
------+---------+------+---------+------+------+---------+
Day | _Ammospiza caudacuta_ | Average |
------+---------+------+---------+------+------+---------+
0 | 1.6 | ... | 1.8 | 1.7 | 1.7 | 1.7 |
1 | 1.8 | 2.3 | 2.5 | 3.0 | 2.1 | 2.3 |
2 | 3.3 | 2.7 | 4.1 | 4.6 | 3.1 | 3.6 |
3 | 5.0 | 3.7 | 5.9 | 6.4 | 4.7 | 5.1 |
4 | 6.8 | 5.4 | 8.4 | 9.1 | 6.7 | 7.3 |
5 | 8.6 | 6.9 | 10.7 | 11.2 | 9.5 | 9.4 |
6 | 10.2 | 8.9 | 12.8 | 13.0 | 10.9 | 11.2 |
7 | 12.1 | 11.4 | 14.5 | 13.6 | 12.3 | 12.8 |
8 | 13.5 | 12.9 | 15.3 | 14.5 | 13.3 | 13.9 |
9 | 12.2 | 13.4 | 15.9 | 14.9 | 13.6 | 14.0 |
10 | 12.7 | 14.0 | 15.5 | 15.0 | 14.0 | 14.2 |
11 | ... | ... | ... | 15.1 | 14.4 | ... |
------+---------+------+---------+------+------+---------+
[1] These weights are not figured in the averages; see text.
Seven nestling Seaside Sparrows and five nestling Sharp-tailed Sparrows
were weighed at 24-hour intervals until they left their nests. The
birds were weighed in early morning before they had received much food.
Weights of these individuals, and daily averages for each species are
shown in Table 1. The weights in the zero column were of nestlings that
had not been fed. The weight of one hatchling (1.9 gm.), which does not
appear in the table, is included in the average for the zero column.
Two young Seaside Sparrows, approximately a week old, fell out of a
nest between 9:30 a.m. July 6 and 5:30 a.m. July 7. When I found them
below the nest, at the latter time, their temperatures were far below
normal, and they had lost a considerable amount of weight. These
abnormally low weights were not figured in the averages. The weights of
Sharp-tailed Sparrows 11 days old were obtained by confining the birds
to the vicinity of the nest with a screen.
[Illustration: FIG. 1. The development of the young of Seaside Sparrows
(solid line) and Sharp-tailed Sparrows (dotted line) as evidenced by
four linear measurements taken at 24 hour intervals.]
At hatching and throughout nestling life and post nestling life Seaside
Sparrows average heavier than Sharp-tailed Sparrows of comparable age
(Table 1). Weights of adults of the two species that were netted or
collected between May 6 and June 27, 1955, within two miles of
Chadwick, Ocean County, New Jersey, follow: Fourteen males of
_Ammospiza maritima_ averaged 24.2 gm. (21.9-27.4 gm.); three females
averaged 22.3 gm. (19.8-24.4 gm.). Thirty-three males of _A.
caudacuta_ averaged 20.7 gm. (18.0-23.1, 25.8 gm.); 14 females
averaged 17.8 gm. (15.3-19.0 gm.), 2.9 gm. less than the males. One
female Sharp-tailed Sparrow, weighing 23.1 gm., was not included in the
averages because it had an egg with shell in the oviduct.
Montagna (1940:195-196) weighed a series of breeding Sharp-tailed
Sparrows (21 males; 5 females) from Popham Beach, Maine, and found the
males to be only 0.2 gm. heavier than the females, but he stated that
the small number of females weighed, and the high percentage of these
that contained eggs, probably lessened the difference in weight found
at other seasons.
The four linear measurements that I took on the same series of adults
confirmed the size difference: Seaside Sparrows average larger than
Sharp-tailed Sparrows, and males average larger than females in both
species. The average and range for each measurement taken on the
sparrows is presented in Table 2.
Four linear measurements were also taken daily on the young sparrows. A
summary of these data appears in Figure 1.
_Behavior_
The first indication of hatching is a crack in the side of the egg
along the line of greatest circumference. The crack is extended along
this line by the egg tooth, and then contraction of muscles of the neck
by the embryo separates the shell into two pieces. Extension of the
legs frees the bird from the shell. I held the eggs of two Seaside
Sparrows in my hand and watched this procedure. In each instance the
young bird defecated in the shell before freeing itself. A barely
audible "peep" note was heard from one hatchling Sharp-tailed Sparrow
when I held it near my ear. When free from the shell, the young birds
rest on their tarsi, abdomen and forehead; their down dries in a few
minutes, and their skin becomes noticeably darker. One sparrow gaped
five minutes after hatching and all the young gaped later the same day.
The abdomen of the young becomes distended when they are fed by the
parents.
[Illustration: PLATE 5
_Ammospiza caudacuta_
_Ammospiza maritima_
Drawings of the nestlings of the two species of _Ammospiza_
approximately three days of age showing the variation in the amount and
placement of the neossoptiles in the two species. Abbreviations for
feather tracts in which downs were found: ca, capital; h, humeral; a,
alar; d, d´, dorsal; cr, crural; v, ventral.]
[Illustration: PLATE 6
An aerial view of the marshes at Chadwick (upper left) and Lavallette
(lower left). The Atlantic Ocean appears in the upper right of this
photograph.]
TABLE 2--LINEAR MEASUREMENTS IN MILLIMETERS OF ADULT SEASIDE SPARROWS
AND SHARP-TAILED SPARROWS CAPTURED OR COLLECTED WITHIN TWO MILES OF
CHADWICK, OCEAN COUNTY, NEW JERSEY, BETWEEN MAY 6 AND JUNE 27, 1955.
=========================================================
_Ammospiza maritima_
--------------+-------------------+---------------------+
| 14 males | 3 females |
--------------+-------------------+---------------------+
wing (chord) | 64.14 (60-66) | 58.33 (58-59) |
tail | 55.28 (54-59) | 51.00 (49-53) |
tarsus | 23.00 (22-25) | 22.17 (21-23) |
culmen | 15.18 (15-15.5) | 14.50 (13.5-15.0) |
---------------------------------------------------------
_Ammospiza caudacuta_
--------------+-------------------+---------------------+
| 33 males | 15 females |
--------------+-------------------+---------------------+
wing (chord) | 58.79 (55-61) | 55.67 (54-58) |
tail | 49.48 (46-53) | 46.93 (45-50) |
tarsus | 20.91 (20-22) | 20.30 (20-21) |
culmen | 13.67 (13-14) | 13.23 (12.5-14.0) |
--------------+-------------------+---------------------+
In the first 24-hour period after hatching the soft "peep" note is
heard frequently. The young are better able to right themselves, and
many feather papillae show distinctly through the skin.
On the second day young are capable of moving short distances by using
their wings and feet. A thick ridge of tissue forms over the eyeball
where the eyelids later delaminate. The call is now a double version of
the "peep" note described above.
When the young are three days old the eyelids open, but only slightly.
In the next three days the young become better co-ordinated and the
eyes open fully. The egg tooth was last seen on a young bird on the
sixth day. All incoming feathers remain sheathed until the seventh day.
On the seventh day young show the first signs of cowering. Previously,
they all begged when I came to the nest. The remiges remain sheathed,
but the body feathers emerge from the tips of the sheaths. A quiet
reedy call replaces the "peep" note. A quiet, but squealing distress
call was also first noted on the seventh day, when the young were
handled.
On the eighth day the remigial sheaths become gray (previously they
were dark blue) and begin to slough off. When removed from the nest,
the young attempt to escape. Begging is less frequent and cowering is
the predominant attitude towards intruders.
The first young of both species left the nest on the ninth day. It must
be remembered, however, that this remark, and succeeding remarks,
concerning departure of young from nests pertains to young that were
disturbed daily by me. The others climbed to the edge of the nest when
they were left alone, but remained in the nest when they were all
replaced. Gaping was recorded once on the ninth day. Stuart W. John
watched two Sharp-tailed Sparrows on my study area leave a nest. They
climbed out and immediately hid in a tussock of grass a few inches
behind the nest.
On the tenth day when I parted the branches over one Seaside Sparrow
nest, the four young jumped from the nest and scattered in the grass.
One of these birds gave a chipping note similar to the distress call of
adults. No bird remained in a nest longer than ten days. Four young
left the nest after nine days, seven young left on the tenth day. When
the young leave the nest they are able to run rapidly through the dense
grass. The young are fed by the parents for approximately 20 days after
they leave the nest. Twenty-three days after one young Seaside Sparrow
left the nest it was netted at the opposite end of the island, 300
yards from the territory of its parents.
Young Seaside Sparrows fly in an uncertain but characteristic manner
when they are flushed from the grass. They dive clumsily into the grass
after a short flight, making it easy to identify them as birds of the
year.
The plumage of sparrows of the Genus _Ammospiza_ serves to conceal them
in their habitat. In juvenal and adult plumage, the Sharp-tailed
Sparrow is a brown-backed, streaked bird, the color and pattern
blending with the matted grasses (Allen, 1925:67) where the species
feeds and nests. The Seaside Sparrow, as an adult, is olive-gray. Its
color corresponds to that of the substratum where the species forages.
The juvenal plumage of the Seaside Sparrow resembles that of the
Sharp-tailed Sparrow. I believe that young Seaside Sparrows have this
brown, streaked plumage because they spend most of their time in the
dense grass. In the Seaside Sparrow a complete post-juvenal molt begins
in late August. The resulting plumage resembles that which is acquired
by the adults when they complete their post-nuptial molt (Dwight,
1900:192-193).
FOOD, FEEDING, AND CARE OF THE YOUNG
The food habits of Seaside Sparrows and Sharp-tailed Sparrows have been
studied by Judd (1901:64-66), who concluded that both species are
highly insectivorous. In 51 stomachs of Sharp-tailed Sparrows 81 per
cent of the contents was animal. The results of investigation of
stomachs of Seaside Sparrows were similar. In each of the two species
the bill is more elongated and less conical than in other sparrows. For
the two species studied, the shape of the bill seems to be an
adaptation for feeding on insects.
When searching for food, Sharp-tailed Sparrows walk through the dense
black grass, deftly brushing stems aside with their bill as they go.
Open areas are generally traversed by rapid running. I never noticed
either species hopping. They stop to investigate openings in the matted
understory of grass, often sticking their heads into the holes. Many
times I saw these sparrows stretch or jump to pick insects from stems.
Many droppings, almost certainly those of Sharp-tailed Sparrows, were
present in areas of damp, matted grass. Females, when feeding young,
obtain most of the food near the nest; several times I saw birds catch
insects when they were within inches of their nest. Sharp-tailed
Sparrows feed also along the banks of pools and creeks, and along the
perimeters of marshes. Sharp-tailed Sparrows seem to be less restricted
in the types of feeding habitats they can use than are Seaside
Sparrows.
Seaside Sparrows always returned to the edge of the marsh to procure
food, according to my observations. The birds at Lavallette fed
extensively on noctuid moths. In the feeding territories of two pairs
of Seaside Sparrows, along the strip of washed-up eel grass, I found at
least 40 wings of these moths. In several instances the four wings of
one moth were lying close together in the same relative position in
which they had been on the animal. Legs and pieces of thorax were also
discarded occasionally. I watched adults take these moths from the
stems of the smooth cord-grass and snip the wings off with their bills.
Moth wings were present in the other feeding territories, but not in so
great a quantity. Once I saw a female return to the nest with a spider
in her bill. Spiders were abundant throughout the marsh.
Dwight (1900:193) was surprised that the two species living in the same
environment, and therefore suffering equally from abrasion from the
coarse marsh grasses, should have a different number of molts per year.
The Sharp-tailed Sparrow has a complete pre-nuptial, as well as a
complete postnuptial, molt. The Seaside Sparrow has only a postnuptial
molt, the nuptial plumage being acquired by wear. My observations of
the feeding habits of the two species indicate that they do not live in
precisely the same environment. The Sharp-tailed Sparrow, which has two
complete molts annually, generally forages in dense, abrasive
vegetation. The Seaside Sparrow, which has but one molt each year,
forages in relatively open areas.
Several times I saw adult Seaside Sparrows fly from their nests toward
the feeding territories with fecal sacs in their bills. On the feeding
grounds, I found several of these sacs discarded near the moth wings. I
saw also female Sharp-tailed Sparrows leave their nests with fecal
sacs. I did not see sparrows of either species swallow fecal sacs.
One nest, that of a Seaside Sparrow containing four young, became
fouled with excrement when the young were nine to ten days old. It is
interesting that these young were cared for only by a male, at least
for the last four days of nest life, and that one of the young birds
died two days before the others left the nest. This male's mate was
probably a female that I banded on June 18 (the young left the nest on
June 23) and never saw again. A female, whose mate was probably killed
by me on June 15, continued to incubate the three eggs until they
hatched on June 29, but deserted the nest when the young were two days
old. This female was seen again on August 1 more than 500 yards from
her nest site on the island immediately north of the study area.
Devotion of parent passerine birds to the young typically increases
with the growth of the young (Nice, 1943:245). This may explain why the
mateless female deserted its nest when the young were only two days
old, whereas a mateless male continued to care for his six-day-old
young. The death of one nestling, and the eventual fouling of his nest
may indicate that the job was too much for one adult to perform. The
correlation of increasing devotion of the parents with increasing age
of the young was further illustrated by the distraction display, noted
by me, on the part of a pair of Seaside Sparrows on the day their young
left the nest. As I lifted the four nine-day-old young from the nest
for weighing, they began to give the distress call. This attracted the
parents from the feeding area approximately 60 yards away. The two
adults ran around on the ground within ten feet of me giving the
_tsip_ note and fluttering their wings. Several times the adults
flew within a few feet of me, making a vibrating sound with their
wings. Although I realized the function of this display, it was
distracting nevertheless.
ACKNOWLEDGMENTS
I am indebted to Assistant Professor Harrison B. Tordoff for
comments and suggestions throughout the preparation of this
manuscript, and to Mr. Stuart W. John who photographed the birds
and the habitat scenes. The aerial photograph of the study island
is reproduced with the permission of Fairchild Aerial Surveys,
Inc., and the photograph of Lavallette and Chadwick through the
kindness of the Lavallette Yacht Club. The drawings were made by
Mr. John R. Beeder. Additionally I wish to express my gratitude to
Dr. Dean Amadon, Mr. H. Lyman Sindle, and Mr. Lester B. Woolfenden
for help and advice in certain aspects of the field work.
SUMMARY
A comparative study of the breeding behavior of the Seaside Sparrow and
Sharp-tailed Sparrow was made in New Jersey in 1955.
Observations of marked individuals indicate that the Seaside Sparrow is
monogamous and territorial, whereas the Sharp-tailed Sparrow is
promiscuous, and at least the male is non-territorial. The male Seaside
Sparrow defends its territory by chasing and singing. The male
Sharp-tailed Sparrow confines itself to a breeding home range. This
range is not a territory; it is inhabited by several males. Female
Sharp-tailed Sparrows may be territorial; this is not certainly known.
The Seaside Sparrow sings louder, more distinctly, more often, and from
more exposed perches than does the Sharp-tailed Sparrow. These
characteristics seem to be correlated with territorial habits. Other
calls are described and their functions are discussed.
The Seaside Sparrow nests in marsh-elder bushes, or in areas of mixed
vegetation. The Sharp-tailed Sparrow prefers the inner, drier areas of
a marsh, where black grass is dominant. The Seaside Sparrow places its
nest farther above the ground than does the Sharp-tailed Sparrow. Both
species used only black grass in constructing the nest.
Copulation is described. The incubation period was not determined for
either species. Three or four eggs seem to be a normal clutch. Females
do all of the incubating.
The young remained in the nests nine to ten days. These nests, of
course were disturbed, for I visited them at least daily. The nestlings
of the Seaside Sparrow are fed by both parents. Male Sharp-tailed
Sparrows seem not to know the location of the nests and take no part in
rearing the young at least up to time of fledging. The natal down of
both species is described. Data on growth and behavior of the young are
presented.
Seaside Sparrows obtained most of their food from the shoreline of the
marsh, in areas of open mud and smooth cord-grass. The plumage of the
adult matches, in color, this mud. The Sharp-tailed Sparrow feeds
everywhere in the marsh, but mostly in areas of dense and matted black
grass. The plumage on the dorsum of this species is brown and streaked
resembling the dead grass. Juvenal Seaside Sparrows, which spend most
of their time concealed in the dense grass, resemble adult and juvenal
Sharp-tailed Sparrows in plumage. Sharp-tailed Sparrows molt completely
twice per year. The Seaside Sparrow molts but once per year. The
difference in number of molts, too, is correlated with habitat
preference, since the grassy forage habitat of the Sharp-tailed Sparrow
must result in greater abrasion of the plumage than does the open
feeding habitat of the Seaside Sparrow.
LITERATURE CITED
ALLEN, GLOVER M.
1925. Birds and their attributes. Marshall Jones Co., Boston,
Massachusetts. xiii + 338 pp., frontispiece, 45 pls., 6 figs.
CRUICKSHANK, ALLAN D.
1942. Birds around New York City, where and when to find them. The
American Museum of Natural History, Handbook Series, No. 13, New York.
xvii + 489 pp., frontispiece, 35 pls.
DWIGHT, JONATHAN
1900. The sequence of plumages and moults of the passerine birds of New
York. Annals N.Y. Acad. Sci., Vol. XIII, pp. 73-360, 7 pls.
FORBUSH, EDWARD HOWE and MAY, JOHN BICHARD
1939. Natural history of the birds of eastern and central North
America. Riverside Press, Cambridge, Massachusetts. xxv + 553 pp., 97
pls.
GRISCOM, LUDLOW
1944. A second revision of the Seaside Sparrows. Occ. papers of the
Museum of Zool., L.S.U., No. 19.
JUDD, SYLVESTER D.
1901. The relation of sparrows to agriculture. U.S.D.A. Bull. No. 15,
98 pp., 4 pls., 19 figs.
LEWIS, HARRISON F.
1920. Notes on the Acadian Sharp-tailed Sparrow (_Passerherbulus
nelsoni subvirgata_). Auk, 37:587.
MONTAGNA, WILLIAM
1940. The Acadian Sharp-tailed Sparrows of Popham Beach, Maine. Wilson
Bull., 52:191-197, 2 figs., 1 table.
1942a. The Sharp-tailed Sparrows of the Atlantic coast. Wilson Bull.,
54:107-120, 4 figs.
1942b. Additional notes on Atlantic coast Sharp-tailed Sparrows. Wilson
Bull., 54:256.
NICE, MARGARET MORSE
1933. The theory of territorialism and its development. Fifty years'
progress of American ornithology 1883-1933. A.O.U., Lancaster,
Pennsylvania, pp. 89-100.
1941. The role of territory in bird life. Amer. Mid. Nat., 26:441-487.