7

Of Blue Jays and Mimicry

Ross D. James

Most of us are aware that Blue Jays species, and present some further (Cyanocitta cristata) are capable of observations of mimicry in Blue giving imitations of hawk calls. Few Jays that suggest a new interpreta­ of us, however, may actually have tion of why the jays mimic. heard a jay doing so, for in my expe­ rience, it is only a relatively few jays Observations that do the imitations. Some people From 23 to 25 August 2000, I may have heard an imitation, but visited a cottage on southern been unaware of what they were Georgian Bay (north of Wasaga hearing. Some of the imitations are Beach). The first afternoon there, I remarkably good, and if heard only, quickly saw and heard Blue Jays in without seeing the caller, a listener the pine trees about the cottages. may consider that it was given by There were single jays, or a few the appropriate species. well-spaced birds, possibly family In a variety of papers relating members, foraging through the to this behaviour in wild birds, the trees. Few other species were about species mimicked include Red­ and none were as noisy as the jays. shouldered Hawk (Buteo lineatus) It was easy to tell what was doing (Nicholson 1936, Bent 1946, James the calling. On the deck in the late 1988), Red-tailed Hawk (B. afternoon, I was soon treated to the jamaicensis) (Baird et a1. 1875, Bent sound of a jay calling loudly in what 1946), Broad-winged Hawk (B. was a very uncharacteristic way. I platypterus) (James 1988, Tarvin expected a hawk call, but could not and Woolfenden 1999), Cooper's identify it as such. There did not Hawk (Accipiter cooperii) (Tarvin seem much chance of any hawk and Woolfenden 1999), Osprey being resident here among the sev­ (Pandion haliaetus) (Atkins 1989, eral rows of cottages extensively Hailman 1990), and American spread along the shores in this area. Kestrel (Falco sparverius) (Baird et Finally, after hearing several a1. 1875, Chapman 1904). Two more calls, it became clear to me species other than hawks also have that it was not what I expected at been mimicked by wild Blue Jays, all, but an imitation of the penetrat­ the Eastern Screech-Owl (Otus ing "scream" of a Ring-billed Gull asio) (Sutton 1977, Tarvin and (Larus delawarensis). There were Woolfenden 1999), and Fish Crow gulls screaming from time to time in (Corvus ossifragus) (Phillips 1993). the background along the shores of To this list I will add another the bay. The cottage, however, was VOLUME 20 NUMBER 1 8

in the third row back from the can hear the Blue Jay much more beach, and all lots were more or less frequently imitating a hawk than I well treed. It was only beyond the ever hear the real hawk. And, more cottages and over the sand dune importantly, the jay imitates the back of the beach before it became hawk at any season of the year. open enough for the gulls. There The hawk imitation by the jay is were no gulls near the jays when most frequently heard in late sum­ they were calling like a gull. The mer or autumn, when the jays are gull calls of the jay were not fre­ more vocal anyway. And I have quent, but a few were rather ran­ heard it when there is snow on the domly given among the more usual ground (although the jays seem to ringing jay calls expected at this retreat to town to the bird feeders in time of year. In other words, the most of the winter). I think I have calls were not associated with any heard it probably at least once a behaviour other than foraging, as month (sometimes several times a far as I could see. The jay doing the month) over the past couple of years. gull call was apparently resident The calling bird may be alone (or here at this time, and I heard at probably within hearing of another least one such call on the three days jay, or jays), or may be accompanied I was there, without spending a by one or more other birds. There is great deal of time where I could never any apparent conflict or have heard it. excitement of any sort. The jay just The second observations of uses it as if it were any other jay call Blue Jay mimicry that are of rele­ to let the world know it is there. vance here occurred near my home. I live in the rolling rural farmland Hypotheses near Sunderland, Ontario, with Numerous explanations have been plenty of wooded areas along the offered to try to explain the func­ Beaver River, and in fence rows. tional significance of the mimicry of For a couple of years now, I have hawks by Blue Jays (Goodwin 1976, been aware of a jay (presumably HaHman 1990, Tarvin and only one) that regularly imitates the Woolfenden 1999). Among the pos­ scream of a Red-tailed Hawk (also sibilities put forward are: an inhabitant of the area). The imi­ tation is a good one, and I have to 1) Enhanced sexual selection dur­ consider where it is coming from ing pairing. Certainly, enlarged song before deciding which species is repertoires are known to enhance actually calling. The jay would the chances of successful pairing reveal itself soon by giving a typical (Howard 1974, Krebs et al. 1978). jay call after initially giving one or However, if this were the reason, several hawk calls. But, the perti­ why would they call in autumn nent point in relating this is that I (more than spring), or even in win- ONTARIO BIRDS APRIL 2002 9 ter? And why imitate only hawks of a raptor. Again, in the numerous instead of any species, as the instances I have witnessed, there mimids do? has never been a hawk anywhere near, and there were not any gulls 2) Mate identification within pairs. close to the jays at Wasaga. And I While individual recognition is imagine the birds are well able to important, not only to pairs, but communicate danger by other calls. also among neighbours, why call at seasons when birds are not closely 6) To indicate where a hawk was paired, and often flocked? And previously. Why bother? Why again, why only hawks? would there be any threat if it was gone? And hawks could be any­ 3) Enhanced territorial defence where, so they would have to use during the mating season. But, the them all over the place. Also, it defence of consistent or extensive would be more beneficial to imitate territorial boundaries is nonexistent an accipiter than a buteo or a Ring­ as far as other Blue Jays are con­ billed Gull. cerned (Tarvin and Woolfenden 1999). Blue Jays do keep away 7) To deceive other species into neighbouring pairs, but neighbours believing a raptor is present. There are the very ones likely to be well seems little reason to do so at most aware that it is only mimicry any­ any time of year other than the way. And why would they call more breeding season. I do not have a outside the breeding season? bird feeder from which jays might be trying to chase other species and 4) Used in mobbing or enhancing jays probably are well able to chase threats to predators approaching off most other species that might nests. While calling like a hawk compete for food anyway. might enhance the chances of dis­ couraging other birds from coming 8) Blue Jays simply incorporate near a nest, why bother using these environmental sounds into their calls in late summer, autumn, and repertoire. While Blue Jays are cer­ winter? And the hawks most fre­ tainly capable of imitating other quently mimicked are buteos, not things (captive birds have imitated particularly dangerous to other cats, whistles, words, and other birds in woodlands. In none of the birds; see Ramsey 1972, Terres many instances I have witnessed 1980), why would they not incorpo­ has there been any evidence of rate the songs of many birds other mobbing. than raptors in the wild? Steller's Jays (Cyanocitta stelleri) incorpo­ 5) To alert other individuals (pre­ rate many other animal sounds sumably jays) to the near presence (Greene et al. 1998). VOLUME 20 NUMBER 1 10

9) Hawk calls are native to the Early in life, a bird is subject to repertoire of jays. Why would the the greatest probability of being calls of hawks be native to jays any killed by a predator. I suggested more than the calls of some other before (James 1988) that perhaps species? If hawk calls were native the raptor calls were learned at a to jays, why would all jays not be time of stress or high excitement using these calls all the time? I have when the birds were learning their seen relatively few jays using hawk calls. Such excitement could be calls. And are we also to suggest caused by a raptor near a nest or a that Fish Crow calls, or Screech­ recently fledged jay, and could pro­ Owl, or Ring-billed Gull calls are vide a model from which to learn. also native to Jays? This would be consistent with their learning only the calls of potential In the end, all we have are pos­ predators, primarily hawks, but also sible uses of hawk calls, that might gulls, owls, and crows. Several apply some of the time, and then authors have noted that Blue Jays apparently apply only with a few often appear to give hawk imita­ individuals. There is some anecdot­ tions at times of high excitement al evidence to suggest some of the (Goodwin 1976, Tarvin and above uses may have happened at Woolfenden 1999). This suggests some place to some birds. But, that they may be given in a situa­ despite more than a century of tion offering a stimulus similar to observations, nobody has a good that in which the calls were learned. explanation that would provide any I have seen very little excitement real functional significance to Blue evident in any of the incidents I Jays imitating raptors. have witnessed, but at least if given at such times, it is consistent with Discussion the stimulus situation that would Most passerine birds learn at least promote the learning only of the part of their vocal repertoire, often calls of predators. by imitating the sounds of neigh­ I would suggest then, that in bouring birds (Kroodsma 1982). most instances, there is probably no Learning is certainly a component of particular functional significance to the development of Blue Jay calling the mimicry of hawk calls by Blue (Tarvin and Woolfenden 1999). Such Jays. These calls are given in a whole learning typically takes place during variety of situations that have sug­ the first few weeks or months of life, gested many functions, none of and once incorporated into a vocal which are supported by any com­ repertoire, a call is likely to remain pelling evidence. This might not pre­ through the life of the bird (Marler clude an individual jay from learning and Mundinger 1971, Nottebohm to use a hawk call in a functional 1975, Marler and Peters 1981). way to its advantage. But, the inci- ONTARIO BIRDS APRIL 2002 11 dence of such functional use of a apparently used just for contact, predator call seems very rare. and often by lone jays not obvious­ Overall, it seems more likely that the ly interacting with other jays or calls are learned inadvertently by a engaged in any apparent social few birds, enhanced perhaps by the behaviour (Tarvin and Woolfenden presence of a calling predator at a 1999). critical time in the life of the jay; What I find intriguing is that we something that is likely to be may be able to test the possibility remembered in more ways than one. that predator imitations have no Young birds are usually con­ particular functional significance strained in what they learn by for Blue Jays. By providing a strong inherited "sensory templates" that novel stimulus to young Blue Jays, allow them to select only certain with recorded calls and/or mounted songs from a rich sound environ­ predators, at an appropriate song ment of many bird species (Marler learning age, we can see what are and Peters 1982). Why Blue Jays the results among those birds as should so easily be able to pick up they mature. The major difficulty a fairly wide variety of types of may be finding the dispersed young predator calls is unknown. again, dispersal being something we However, Blue Jays are very vocal, apparently know nothing about. using many variations of typical calls, with many calls used in multi­ ple contexts, such that functions of Perceptor Brownsville Junction Plaza, anyone of them are difficult to Box 38, Suite 201, identify (Tarvin and Woolfenden Schomberg, Ontario LOG ITO SERVING BIRDERS FOR OVER 20 YEARS 1999). Some of the hawk imitations FRIENDLY SERVICE EXPERT ADVICE LOW PIOC'e> are considered to be variations of Binoculars, Spotting S~opes, Telescopes, their usual "jeer" call (Tarvin and Tripods and A~cessories Woolfenden 1999). Variations on Popular Brands - includingSwarovski existing calls, and a fairly wide Orderconveniently by phone, or facility to improvise, may provide visit ourshowroom in the plaza west side of Hwy '1:7, 1/2 mile south of Hwy 9. jays with the ability to learn novel 2nd Door(via blue door offcourtyard) sounds especially with a strong WedJlesday lOam to 6pm ,. Closed on some stimulus. Then, once the calls are Thursday lOam to 6pm summer Fridays Friday • lOam to 6pm and Saturdays incorporated into the repertoire, Saturday• lOam to 4pm - please call - they become just a part of their Phone: 905·939-2313 calling. Hawk (owl or gull) imita­ Ifthe above number is "long distance" tions would serve the same func­ from your area, then call ... tion as typical "jay" or "jeer" calls toll free: 1·877-452-1610 Fax: (905) 939..8274 that are used in many contexts and Major Credit Cards accepted situations. While the "jeer" call 2.S% discount for cash or cheque may be used in mobbing, it also is VOLUME 20 NUMBER 1 12

Literature Cited Atkins, A. 1989. Blue Jay imitates Osprey. Marler, P. and P. Mundinger. 1971. Vocal Oriole 52: 48. learning in birds. In The Ontogeny of Baird, S.F., T.M. Brewer, and R. Ridgway. Vertebrate Behavior (H. Moltz, editor). 1875. A History of North American Birds. Academic Press, New York. Volume II. Little, Brown and Co., Boston. Marler, P. and S. Peters. 1981. Sparrows learn Bent, A.C. 1946. Life Histories of North adult song and more from memory. American Crows, Jays, and Titmice. Science 213: 780-782. United States National Museum Bulletin Marler, P. and S. Peters. 1982. Subsong and 191, Washington, D.C. plastic song: their roles in the vocal learn­ Chapman, F.M. 1904. Handbook of Birds of ing process. In Acoustic Communication Eastern North America. D. Appleton and in Birds. Volume 2 (D.E. Kroodsma and Co., New York. E.H. Miller, editors). Academic Press, Goodwin, D. 1976. Crows of the World. New York. Comstock Publishing Associates, Ithaca, Nicholson, D.J. 1936. Observations on the New York. Florida Blue Jay. Wilson Bulletin 48: Greene, E., W. Davison, and V.R. Muether. 26-33. 1998. Steller's Jay (Cyanocitta stelleri). In Nottebohm, F. 1975. Vocal behavior in birds. The Birds of North America, No. 343 (A. In Avian Biology. Volume 5 (D.S. Farner, Poole and F. Gill, editors). The Birds of J.R. King, and K.C. Parkes, editors). North America, Inc., Philadelphia. Academic Press, New York. Hailman, J.P. 1990. Blue Jay mimics Osprey. Phillips, J.D. 1993. Blue Jay vocalization Florida Field Naturalist 18: 81-82. resembles Fish Crow. Redstart 60: 53. Howard, R.D. 1974. The influence of sexual Ramsey, A.O. 1972. Mimesis in hand-reared selection and interspecific competition on Blue Jays. Bird Banding 43: 214-215. mockingbird song (Mimus polyglottos). Sutton, G.M. 1977. Fifty Common Birds of Evolution 28: 428-434. Oklahoma and the Southern Great Plains. James, R.D. 1988. Blue Jays mimic the calls University of Oklahoma Press, Norman, of Red-shouldered and Broad-winged Oklahoma. Hawks. Ontario Birds 6: 11-14. Tarvin, K.A. and G.E. Woolfenden. 1999. Krebs, J.R., R. Ashcroft, and M.I. Webber. Blue Jay (Cyanocitta cristata). In The 1978. Song repertoires and territory Birds of North America, No. 469 (A. Poole defense. Nature 271: 539-542. and F. Gill, editors). The Birds of North Kroodsma, D.E. 1982. Learning and ontoge­ America, Inc., Philadelphia. ny of sound signals in birds. In Acoustic Terres, J.K. 1980. The Audubon Society Communication in Birds. Volume 2 (D.E. Encyclopedia of North American Birds. Kroodsma and E.H. Miller, editors). Alfred A. Knopf, Inc., New York. Academic Press, New York.

Ross D. James, R.R. 3, S1480, Concession 7, Sunderland, Ontario LOC lRO

ONTARIO BIRDS APRIL 2002