Johnson and Haight • BIOLOGY AND STATUS OF BLACK CATBIRD 
231 
RESULTS 
Territoriality.— The Black Catbirds on NTC 
spent most of the time out of view in thick 
buttonwood groves. Territorial males were fierce¬ 
ly defensive when in the open on the ground or in 
sparse vegetation and seldom allowed other 
catbirds or a person to approach any closer than 
10-15 m. They challenged other catbirds that 
intruded on their territories, pursuing them on the 
ground, in the air. and through vegetation. 
Although demonstrating strong intraspecific terri¬ 
toriality they showed no interspecific territoriality 
toward the Mangrove Warbler ( Dendroica petechia 
bryanti ) or White-crowned Pigeon ( Patagioenas 
leucocephala), the only two other avian species 
occurring regularly in the buttonwood-coconut 
ecosystem on NTC. The White-crowned Pigeon, 
also a near threatened species (1UCN 2010), stayed 
high in the crowns of coconut palms, above 
catbirds, but a male Mangrove Warbler commonly 
fed within 2 m of a Black Catbird without signs of 
aggression by either species. 
Buttonwood groves were widely scattered on 
our 3-ha plot. The defended territory of the pair 
(A) studied most extensively was 100 X 25 m, 
centered on a buttonwood grove and including 
numerous coconut trees. Little herbaceous vege¬ 
tation grew in sandy soil between the coconut 
palms and buttonwood trees other than seashore 
spiderlily ( Hymenocallis littoral is). There were no 
Black Catbird territories to either side of territory 
A and none to the east, but a territorial pair (B) 
often threatened from the west. When followed, 
catbird A would fly ahead of us to the east beyond 
its 100-m territorial edge by -25 m and, when it 
chased intruder B, it would fly 15-20 m past its 
western territorial edge. Thus, the entire length of 
area occasionally used by pair A was -140 m. 
We could only assume that most aggressive 
interactions between two or more Black Catbirds 
were generally between males due to the lack of 
sexual dimorphism. However, on one occasion, 
four Black Catbirds became involved in a 
squabble that lasted ~3 min in and around the 
favored buttonwood. At the end of the squabble, 
after two catbirds (apparently pair B) had flown 
west, the two remaining Black Catbirds (appar¬ 
ently pair A) faced each other on the bent 
buttonwood trunk ~60 cm above the ground. 
Both remaining birds did partial wing-flashes with 
both wings, while spreading their tails; one then 
flew toward the center of the territory. The 
remaining catbird flew to the ground, did a full 
wing-flash and followed in the same direction. 
Perches and Singing Posts— The Black Catbird 
usually remained within 2 m of the ground except 
when singing, often hopping from the ground onto 
a low stump or leaning tree trunk, then back to the 
ground again. It often sang from a prominent, 
open perch such as a slump, bare limb of a tree, or 
occasionally near the top of a medium-sized 
coconut tree, usually 8 m or less in height. Rarely, 
they sang from within tree crowns, e.g.. at least 
three individuals remained hidden from view 
while singing in a dense buttonwood grove at 
— 1130 hrs on 24 June. 
Wing-Flashing and Tail-Fanning. —The Black 
Catbird used both partial and full wing-flashing, 
raising its wings part way or fully extending them 
similar to that of the Northern Mockingbird. 
(Mimas polyglottos). Occasionally a catbird would 
raise only one wing. We noted the Black Catbird 
wing-flashing during territorial battles, while for¬ 
aging. and toward a presumed mate. Tail-fanning 
also, at times, accompanied wing-flashing, similar 
to that of the Gray Catbird. A Black Catbird on the 
ground often engaged in wing-flashing when 
confronting an intruder. A chase on foot might 
follow after a wing-flash before the intruder took 
flight, followed by the territorial bird. 
Foraging and Food. —The Black Catbird at 
NTC foraged extensively among the debris under 
buttonwood trees. One would stop to flick debris 
aside with a sideways movement of its bill then 
move forward a meter or less and repeat the action 
in a manner similar to the Gray Catbird. 
Occasionally, on stopping, the catbird would do 
a double wing-flash before tossing leaves aside. 
They were apparently feeding on invertebrates 
(e.g., insects and spiders) since we could find no 
edible vegetable material among the leaves and 
dried buttonwood fruit. The only seeds to be 
expected would be tiny buttonwood seeds. 
We observed a Black Catbird feeding franti¬ 
cally on the ground in the buttonwood grove 
~10 m outside our cabin window at 1005 hrs on 
24 June. After —l min it flew to the adjacent 
favored buttonwood and another catbird, appar¬ 
ently its mate, flew to the ground and fed for 
— 1 min more at the same spot then joined the first 
in the favored buttonwood. Close examination of 
the area showed that ants were carrying termites 
and termite eggs from a broken termite tube to 
their nest and the two catbirds had been feeding 
on ants and/or termites. 
