FEEDING BEHAVIOR

Peregrine feeding on in Suriname, South America

With noteson predationby other membersof the genusFalco

Jan Erik Pierson and Paul Donahue

ATSARE AN ABUNDANT potential food at duskand againnoted a Peregrine,pre- tion indicatesthat the male may have sourcein the New World, especially sumably the same individual, pursuing beenterritorial at this site throughoutits m the Neotropics(Morris, 1965andpers. bats.The duskbat flight wasalready well winter stayin Paramaribo.Additionally, obs ), and a numberof raptorshave been under way, and hundredswere crossing we believethat it is quitelikely, although reportedto feed on them. Publishedre- the river from the city. Donahue ob- by no means certain, that the 1979 and portson bat predationin the Neotropics servedthe falconhunting for 25 minutes, early 1981 sightingsalso were of the includeAplomado Falcon, Falcofemor- during which time it capturedtwo bats sameadult male. Donahueagain noted an ahs (fiYench, 1967), Bat Falcon, F. ruff- duringtwo sallies(a sally being defined adult male at the waterfront on December gularis (Brown & Amadon, 1968, Cade, here as the time spentaway from a hunt- 19, 1981. If this wasthe sameindividual, 1982), Orange-breastedFalcon, F. deiro- ing perchin activepursuit of prey). After it would representa return to the same leucus (Cade, 1982), Merlin, F. colurn- eachcapture it flew backtoward the city, winter site in at least three out of four bartus (Bent, 1938), Broad-winged apparentlyto feed. On January28 both years. Hawk, Buteoplatypterus (Norris, 1953), authors went to the waterfront to watch In 1981the Peregrineregularly hunted Barn Owl, Tyro alba (Hayerschmidt, for the Peregrineat dusk. On this occa- batsat dusk,and, although we madeonly 1968), Tropical Screech-Owl,Otus cho- sion the Peregrinewas notedfor the first one morningobservation, we believe the hba (Walker et al., 1964), and reportsat time perchingin a tall radiotower (tower probablyhunted regularly at dawnas two locationsfor the PeregrineFalcon, F. A), approximately55 m highand located well. We observedthe Peregrinefor a peregrinus (Sick, 1961, Sprunt, 1951, approximately50 m from the river. Dur- total of 6 hours40 minutes,including six and Stager, 1941). ing three hunting sallies observedthat completedusk huntingsessions and one During two trips to Surinamein 1979 eveningthe Peregrinecaptured a total of completedawn sessionand a total of 28 and 1981we had the opportunityto make four bats, includingtwo duringthe first separatesallies. a seriesof observationson a Peregrine sally. A total of eightattempts was made. The duskbat flight from the city typi- Falconfeeding on bats in the capitalcity We do not know if this representeda cally started at about 1800 hours, ap- of Paramaribo. complete hunting session.During this proximately45 minutesbefore complete Paramaribo is situated on the west and all subsequentobservations the darkness. The Peregrine would often bank of the Suriname River, approxi- plumageindicated that the falconswere starthunting before any batswere visible mately 40 km upstreamfrom its outlet of the migratory race F.p. tundrius to us and would continue through the into the Atlantic. At the capital the river (White, 1968). heavy flight of bats between 1810 and is approximatelyone km wide. A large 1830 hours. Although many bats were numberof bats roostsin or near the city PONOUR RETURN toSuriname inJan- still visible, the bird usuallywould retire during the day, and thousandscan be uary of 1981 we again found a Per- to its roost in tower B for the night by seenflying acrossthe river to and from egrinein residencein Paramariboand de- 1835 hours, by which time it may have the city at dawn and dusk. Our observa- cided to make a series of observations of been too dark for effective pursuit. Our tions suggestthat, by size, shape,and its huntingtechnique. We believethat, at one morning's observationsshowed, in behavior, the bats belong to the family least through our 1981 observations, terms of lighting conditions, approxi- Molossidae, genus Molossus (G. from January 14 to March 2, our sight- mately the same timing in reverse. McKracken, pets. comm.). These are ings refer to the same individual. This common insectivorousbats widespread assumptionis supportedby the consistent UR OBSERVATIONSSUGGEST that, in the Neotropics(Walker et al., 1964). appearanceof the bird's plumageand when it was inactiveduring the day Husson(1962) supportsour conclusion size and by our observationof an aggres- andnight, the Peregrinewould roost high describingMollossus mollosus and M. sive interaction between this individual, on tower B, usingtower A asthe take-off ater as the most common insectivorous by size presumeda male, and an intrud- point during huntingsessions and also bats roostingin buildingsin Suriname. ing female. While the male was perched returning there to consume its prey Donahue first observed a Peregrine in tower A, the female approachedthe These two towers are by far the highest chasingthese bats during a late afternoon area and perchedhigh in a nearbyradio points near the waterfront. A typical visit to the city's waterfronton January tower (tower B), approximately60 m tall hunting sequence included departure 25, 1979. The falcon made several at- and located 250 m from the river. The from tower A and a long steadyclimb or temptsat takingbats but no capturewas male immediately flew to tower B and spiral to gain heightover the bats, which observed.Donahue returned the next day chasedthe female away. This observa- typically flew 25-70 m above the river,

Vol 37, Number 3 257 the Peregrinewould pause momcntardy minutes During this time a minimum of which may havebeen captured by a Per- at the top of its rise, angledownward, 155 capture attemptswas made and at egrine. give a numberof powerfulwingbeats to least 19 bats were taken. Never more than gain speed,then set its wingsfor the onebat per sallywas taken in 1981.Thus stoop.If successful,the bird would either duringour observationsthe averagesally snatch the bat in mid-air or strike it, stun- time was 3 minutes 26 seconds, and an EinstancesKNOW OFof ATbat LEAST hunting three by otherPer- rangit or killing it instantlyand causing it averageof 8.16 attemptswere madefor egrines.Sick (1961, in Brazil)and Stager to tumble down, whereuponthe Per- everybat captured.This representsasuc- (1941, and othersat the samelocation in egrinewould swoopdown to catchthe cess rate of 12.2%. Ratcliffe (1980), Texas) have reportedPeregrines preying bator failingthat, pick it from the surface however, suggeststhat many chasesmay on bats. Both of these cases involved one of the river. Occasionallya bat wouldbe not be actualattempts at prey capturebut or more Peregrinesattacking concentrat- hit but would recover and continue may insteadbe play, makingthe success ed groupsof Brazilian Free-tailed Bats flying. Upon capture,prey was carried rate of captureseem lower than it is. This (Tadarida braziliensis, also Molossidae) back to tower A for consumption.We couldalso be the casewith our Peregrine. as they left their roosts in caves. Our never observedprey eatenin the air, as Sometimes he would seem listless in its 1979and 1981sightings differ from these mentionedby Sprunt(1951). If the Per- effortsto capturea bat and yet on other two publishedreports in that the bats in egrinefailed to hit a bat, it wouldopen its occasionswould appearto take preywith Paramaribo were evenly distributed in wings to brake, sweep up, often make great ease. The minimum numberof at- flight over a large area. Batswere visible what looked to us like a half-hearted sec- temptsper sally was onewhile the maxi- crossingthe river for at least two km ond attemptat the samebat, or simply mum was 29. alongthe waterfront.Lastly, on Novem- beginclimbing again for the next stoop. During the six dusk sessionsthe bird ber 11, 1976, Donahue observedan im- On two occasions, however, the Pere- captured18 bats for an averageof three maturePeregrine make an attemptat cap- grine made a seriesof three attemptsat bats per session.The one morning ses- turingan insectivorousbat (probably also differentbats in one continuoussloping sion we observedyielded only one cap- a Molossid)at dawn in the CaroniSwamp stoop,pulling up only after missingthe turc for four sallies before the bird ap- in Trinidad. third bat. pearedto roost for the day. We do not In tropical SouthAmerica three other- know if this apparentdiscrepancy be- members of the genus Falco also are tween eveningand morning capture rates known to take smallbats as prey. ffrench LTHOUGH'FHI5Peregrine was seen to is representativeof the bird's daily feed- (1967) has observedAplomado Falcon approachbats from virtuallyall di- ing habits throughoutits winter stay in hunting Molossid bats in Trinidad The rections,the mostcommon approach was Suriname. Orange-breasted Falcon "commonly from the rear. During a stoopbeginning Sincewe did not observethe Peregrine catches bats ..... in the air and shows a above and behindthe bat, the bird typi- for an entireday, we are alsonot certain decidedly crepuscularpattern of activ- callywould drop slightly below the level how much of the bird's total huntingef- ity" (Cade, 1982). The Bat Falcon is of the bat and rise to strike it. This ap- fort thesemorning and eveningsessions probablythe commonestand most wide- proachfrom the rearmay, as suggcsted represent.It hasbeen noted (Beebe, 1974 spreadof the falconswhich prey on bats byRodriguez (1972), take advantage of a andpets. ohs.) that thereis a strongpref- in tropical SouthAmerica. It is probably blindspot in the prey'ssphere of vision. erence among Peregrinesfor huntingat also the speciesof raptor which preys As suggestedby Brown (1976), the dawnand dusk. It is possiblethat the bird mostregularly on batsin thisarea (Brown Peregrineappeared to chooseits prey occasionallychased Rock Doves, Co- and Amadon, 1968, Cade, 1982, and while still perched.It would lcave the lumba livia, during the day as we ob- pets. obs.). As with Peregrineand Or- tower in a specificdirection and contin- served two such pursuits, both unsuc- ange-breastedFalcon, it is alsodecidedly ue, undistractedby othernearby bats that cessful, during evening sessions. crepuscularin its hunting (Cade, 1982, seemedto presenteasy targets,until it However, we believe that additional and pets. obs.). In Surinamewe have had apparentlysecured the desiredposi- huntingduring the day is unlikelyconsid- twice observedthis speciespursuing Mo- tion above its chosenprey. ering the abundanceof prey and the ease lossid bats at dawn, once over marshes The Peregrineshowcd a strongprefer- of capture at dawn and dusk. Also, and once over forest and forest edge encefor huntingover the river ratherthan Brown and Amadon (1968) have noted Donahue also frequentlyhas observed the city. Of 28 sallies,21 (75%) were that the food requirementof a Peregrine Bat pursuing bats in eastern over the river. This apparentpreference in warm weather is about 11-12% of its Peru, primarily over lakes and rivers in probablyis relatcdto thedifficulty of re- body weight. According to White forested regions, and almost always at tnevingfallen prey from busycity streets (1968), the weightsof adult male F. p. dawnor dusk.A fourthspecies of Falco, or rooftops.Brown ( 1971), in discussing tundriusrange from 550 to 647 g. Thusa the Merlin, a winter resident in coastal the feedinghabits of the Bat Hawk, Ma- daily average consumptionof at least areas of tropical South America, can chaerhamphusalcinus, of Africa, and four and possiblyas many as six Molos- probablysafely be assumed,during this Beebe (1974), in discussingPeregrines, susbats, eachweighing 10-30 g (Walker time, to feed on bats as well. It has been also have suggestedthat open areasare et al., 1964), would seem sufficient to observedby us in areaswhere Molosstd preferredbecause they presentan unob- meet the bird's food needs. It should be batsare common,and alsohas a crepus- structedline of sight to the prey and a noted that we did not observe the bird to cular patternof activity (pets. obs.) uniformbackground color againstwhich discardany uneatenparts. The bird ap- WinteringPeregrines in Surinamemay to see the bats, and becausehigh speed peared to consumethe entire bat. Al- at times compete for bats with resident chases are safer there. thoughwe searchedthe areabeneath the Bat Falcons,although the two speciesare The 28 sallieswe observedduring the towersfor prey remains,none could be generallysegregated by habitat.In Sun- seven sessions covered a total time of 96 found other than those of a Rock Dove name, Bat Falconsusually are seenover

258 American B•rds, May-June 1983 Drawing / Keith Hansen forestor near forestedge, and especially and direct flight, which may make them ecology. A & W Publishers,New York. along rivers, in the interior and in the easier to catch than bats with a more er- BROWN, L. and D. AMADON. 1968. Ea- coastalregion. On the other hand, Per- ratic flight. Whetheror not thesebats are gles, Hawks, and Falcons of the World. McGraw Hill, New York. egrinesfavor large open areas, suck as heavily contaminatedby pesticidesin CADE, T. J. 1982. The Falcons of the World. beaches and marshes, near the coast, as $uriname and other areas of Central and Comstock/Cornell Univ. Press, Ithaca. well as the immediatevicinity of Para- South America is unknown. However, COCKRUM, E. L. 1970. Insecticides and maribo. Although we have never ob- being insectivorous.Molossus bats could guano bats. Ecology 51:761-762. served Peregrinesover forestedareas in easily accumulatepesticides, including tRENCH, R. P. 1967. The Dickcissel on its Suriname,nor Bat Falconsalong the im- DDE, sincethey forageover agricultural wintering grounds in Trinidad. Living mediate coast or in Paramaribo, there is areas. Chiorinated hydrocarbonpesti- Bird. 6:123-140. someoverlapping over large marshyex- cides are known to have been, and still HAVERSCHMIDT, F. 1968. The of Surinam.Oliver & Boyd, Edinburgh. pansesand large agriculturalareas near maybe, heavilyused in agriculturalareas -: 1972. Bird records from Suriname. the coast ...... areas where Molossid alongthe Surinamecoast (Haverschmidt, Bull. Brit. Ornith. Club 92:49-53. bats are very common. Competitionin 1968, p. 91. underPurple Gailinule en- HUSSON, A.M. 1962. The Bats of Surin- Suriname between Peregrinesand the try). In New Mexico, the drasticdecline ame. ZoologischeVerhandelingen. Lei- other three speciesof bat-eatingfalcons in Brazilian Free-tailed Bats, at the Carls- den, 58:1-282. is probablynegligible. Orange-breasted bad Cavernsis thoughtto be attributable MORRIS, D. 1965. The Mammals -- A Falcon and Apiomado Falcon are both to pesticidepoisoning (Cockrum, 1970). Guide to the Living Species.Harper & rather rare in the coastal area of Suriname To further assess the role of bats in the Row, New York. (pets. obs.), and the Merlin hasyet to be diet of Peregrines,other instancesof bat NORRIS, R. A. 1953. Broad-wingedHawk recordedfor the country(Hayerschmidt, hunting shouldbe watchedfor carefully (Buteoplao'pterus ) feeds on EveningBat. Auk 70:87. 1968). in other areasof the Neotropicswhere Peregrinesoccur. RATCLIFFE, D. 1980. The PeregrineFal- con. T. & A.D. Poyser,Calton, England. A LTHOUGHTHETOTALWinteringpopu- RODRIGUEZ, F. 1972. "The PeregrineFal- ACKNOWLEDGMENTS lation of Peregrinesin Surinameis con: ace of bird hunters" in chapter60, not known, they are not rare and can be World of WiMlife 5:94-119. Orbis Pub- seenregularly in small numbersnear the HE AUTHORSWISH to thankDr. lishing,London. coast during the northern winter (Ha- Charles E. Huntingtonof Bowdoin SICK, H. 1961. PeregrineFalcon hunting bats verschmidt, 1972, and pets. obs.). Our College and Elizabeth Cary Piersonfor while wintering in Brazil. Auk 78:646- observationof a largefemale in the Para- their comments on an earlier draft of this 648. maribo area in 1981 may indicate that manuscript. SPRUNT, A. Jr. 1951. Aerial feeding of more than one Peregrineuses the abun- Duck Hawk, Falco peregrinus anatum. Auk 68:372-373. dant bats as a tbod source there and that LITERATURE CITED theremay be competitionfor suitabletall STAGER, K. E. 1941. A groupof bat-eating BEEBE, F. L. 1974. Field Studies of the Fal- Duck Hawks. Condor 43:137-139. huntingperches. coniformes of British Columbia. Occa- WALKER, E. P., et al. 1964. Mammals of sionalpaper of theBritish ColumbiaProv. Consideringthe widespreaddistribu- the World. The JohnsHopkins Press. Bal- Mus.. 17. tion and abundance of Molossus and oth- timore. er small bats in Suriname and elsewhere BENT, A. C. 1938. Life Histories of North AmericanBirds of Prey, Part 2. (Reprint- WHITE, C. M. 1968. Diagnosisand relation- in the Neotropics,these may represent an ed: Dover Publications,New York. 1961) shipsof North Americantundra-inhabiting important winter food source for Per- BROWN, L. 1971. African birds of prey. PeregrineFalcons. Auk 85:179-191. egrines. Additionally, Molossus bats HoughtonMifflin, Boston. -- RFD # l may be preferredbecause of their high : 1976. Birdsof prey-- their biologyand SouthHarpswell, ME 04079.

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