that biologically significant sounds may have 
practical value for attracting desirable species 
or for repelling pest species, 
An active bioacoustics research program has 
been underway in France since 1950, when the 
Laboratoire de Physiologie Acoustique was 
founded. Emphasis is on research on acoustical 
bird distress signals and their practical appli- 
cation to agriculture. Fundamental research 
is being conducted on the semantics of a 
signal, its physical characteristics, species 
interspecificity, and the type of equipment 
required. Basic factors in the efficacious 
signals are being sought, particularly for the 
Corvidae and starlings. Present crop protec- 
tion from birds in France is based almost 
solely on the use of distress calls. The tech- 
niques are the result of experiments con- 
ducted since about 1954. Cropland can be 
efficiently protected from _ rooks 
frugilegus), jackdaws (Corvus monedula), and 
carrion crows (Corvus corone) for 2 weeks. 
An interspecific reaction has been observed in 
that the distress call of any one of these 
species will also protect the crops from the 
others. Distress calls have been used for as 
long as 2 months against Corvidae at a pear 
orchard without waning effects. When distress 
calls were used against nesting carrion crows 
for several days, the birds appeared to become 
disoriented--some left the nest and some sat 
beside the nest. A collection of eggs indicated 
that incubation had been interrupted (124). 
Considerable research has been conducted 
in Germany since 1959 to develop acoustical 
methods for repelling starlings from vine- 
yards and cherry orchards. German research 
workers report better success with two star- 
ling alarm calls they have recorded than with 
the distress call used by most other workers 
(Keil, pers. commun., 1962). During the 1961 
damage season, starlings were repelled from 
50 acres of grapes for 7 weeks by broad- 
casts of the two starling alarm calls (122). 
Six loudspeakers were used, and the cost of 
protection was $25 per acre. Starlings were 
also successfully repelled from an isolated 
2-acre cherry orchard, but the problem of 
protection is considerably more difficult where 
orchard tracts are continuous and birds can 
move from orchard to orchard (Bruns, pers. 
commun., 1962). Starling distress calls have 
been used in combination with pyrotechnics 
(Corvus 
187 
to disperse starlings from fall roosts (Koenig, 
pers. commun., 1962). In England, starling 
distress calls have been used with limited 
success to repel birds from orchards and 
woodland roosts (124). 
In the United States, the starling distress 
call has been used to repel starlings from 
seedless grape vineyards (20, 1562) and to 
discourage starlings from roosting in English 
holly (Ilex aquifolium) (155). Alarm or distress 
calls of the following species are now being 
used for alleviating damage in vineyards, 
cattle feedlots, and spring lettuce: House 
finches (Carpodacus mexicanus), red-winged 
blackbirds, yellow-headed blackbirds 
(Xanthocephalus xanthocephalus), Brewer's 
blackbirds (Euphagus cyanocephalus), robins 
(Turdus migratorius), and horned larks 
(Eremophila alpestris) (20). In other tests, 
birds were successfully repelled from a 14- 
acre feedlot during an entire damage period 
using amplified distress calls of a starling, 
adult female redwing, and adult female 
Brewer's blackbird, interspersed witha marsh 
hawk (Circus cyaneus) call. At another larger 
feedlot, tests using partial sound coverage 
combined with the use of poisoned bait were 
less successful (110). Distress calls of red- 
winged and yellow-headed blackbirds were 
broadcast from _ stationary units, a mobile 
truck-mounted unit, and a portable unit in an 
airplane in evaluation tests for repelling these 
species from corn (110). Results have been 
variable. Birds can be frightened from corn- 
fields with the airplane-distress-call combina- 
tion, but are persistent in returning. This con- 
trol method does not appear to be economically 
feasible at this time for use in corn. 
Broadcast distress calls of the black-footed 
albatross (Diomedea nigripes) and the Laysan 
albatross (Diomedea immutabilis), helicopter 
and other aircraft noises, pulses of random 
noise, and a series of pure tones were used 
on Midway Island to evaluate the relative 
effectiveness of various sounds as acoustic 
barriers to the Laysan albatross. Some suc- 
cess was reported in affecting the movements 
of flying albatross by using the black-footed 

2 Research results by Zajanc (156) for air horns, 
bird distress calls, and shell crackers in vineyards 
and carbide exploders in fig orchards are based ona 
cooperative program with the University of California 
and the California State Department of Agriculture, 
