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.