Ask Dr. Tom: Vocal Recognition in Wild Turkeys

Anyone who has spent time hunting spring gobblers can relate to the experience of working a bird that either will not answer a call or answers only certain types of calling devices. There is no doubt that is why most turkey hunters carry a suitcase full of calls into the woods. The typical vest includes two or more diaphragm mouth calls (with different numbers and cuts of reeds), at least one box call, a slate or two, a ceramic, glass or aluminum call and perhaps a wing bone, trumpet or tube call. If your experience is typical of the rest of us gobbler chasers, there are likely gobblers that rode home in your truck that refused to answer a box call but enthusiastically responded to a mouth call. Or gobblers that ignored a raspy or clear mouth call but gobbled hard at yelps from a box call. And then of course there are those gobblers that never answered anything from your bag of tricks.

I recall moving in on a late season gobbler on the roost one warm, still morning. He gobbled a few times on his own and responded to a tree call on a slate. After he flew down, he never answered another call though I tried mouth calls and a box. He did, however, gobble once or twice giving me a clue about his destination: a picked 50-acre corn field. I eased over to the field an hour or two after the last gobble. From a hide along the field edge, I could see him feeding more than a hundred yards away. Yelping softly or loudly produced no response whatsoever. Neither did clucks or purrs. I scratched in the leaves and his head came up briefly. Was he interested? After 20 or 30 minutes watching with binoculars, I scratched again. His head rose. Then I purred on a slate call. The feathers on his back stood up. Two or three purrs, some leaf scratching over the course of an hour, and he was in range.

That experience and many others beg the question, “Can wild turkeys recognize the voices of their flock mates, siblings or brood hens and differentiate them from the voices of other turkeys? And of course, can wild turkeys recognize the sound of different calling devices when hunting pressure is heavy? 

The answer to the first question is yes. The answer to the second question is yes, sometimes. Turkeys are social animals and there is a hierarchy or pecking order within and among flocks. The top-ranked bird is dominant over all others, the second in rank is dominant over all but the top bird and so on down the line to the lowest-ranked bird, which is submissive to all others. For this type of social organization to exist, turkeys must be able to recognize every member of the flock as an individual, and turkeys have an exceptional ability to recognize each other by voice and by facial characteristics. The turkey’s ability to recognize individual vocalizations is on par with human ability to recognize human voices. For Eastern wild turkeys, flock size is generally small, but under some conditions flocks of several hundred can form. When large groups form there is a pecking order within and among flocks.

Now, to our second question, can turkeys recognize the sound of different calling devices and become “call shy?” We think turkeys interpret the sound made by different calling devices as the voices of different turkeys. Every time you change calls you become a different turkey! That helps explain the different reactions of gobblers described at the beginning of this story.

We also think turkeys can become “call shy” because of their skill at recognizing individual voices. Our efforts to count the number of poults in wild turkey broods revealed that hens could recognize and remember tape-recorded poult calls. Poults are notoriously difficult to count in the field, so we tried to count broods by using recorded poult calls to attract radio-tagged wild turkey hens. Calls of 2-week-old poults held in isolation were recorded. The call is a series of peeps ascending in pitch and volume given by poults that have been separated from the hen. The calls were recorded on a three-minute loop and played on a small tweeter speaker. The first time a hen heard this call she responded immediately and rushed to the speaker. On the second exposure, the hen’s response was less vigorous – she approached and called but would not leave cover. On the third trial, hens vocalized and moved away from the recorded call. I am convinced hens recognized the call after a single exposure. The “lost poult call technique” never worked well. The original idea was that we could get the hen and brood to cross a forest road (or field edge) to reach the speaker, and thus get an accurate count. But, when hens responded vigorously they also scattered the brood, and the poults hid. That experience gave us insight into the hens’ ability to recognize and remember calls. There is no reason to think adult males do not have the same ability. If you fool a gobbler once with your favorite call and he survives, you probably will not get a second chance with that call.

Wild turkeys are vocal critters. Lovett Williams working with the Florida subspecies recorded at least 28 calls, each having different functions or carrying a different message. That is not a big vocabulary by human standards, but it is impressive in the bird world. Turkeys are not territorial; they are social. They live in flocks with stable pecking orders. They have large home ranges that vary in size and shape through the seasons, and they share home ranges with many other flocks. Their various calls coordinate the activities of flock mates as they move through the habitat and when they encounter other flocks. All the calls recorded by Williams fell within the range audible to humans, but most observers think the turkey’s ability to hear is superior to ours especially for faint and high frequency sounds.

The gregarious nature of wild turkeys contrasts sharply with that of territorial birds, which include many common song birds. Males of these species have fixed territories that they share with their mates and from which they exclude other males. Their songs are used to delineate territory boundaries and attract mates. The wood thrush, a neotropical migrant bird that nests in North America and has a particularly beautiful song, sheds some light on the territorial lifestyle. In addition to its complex flute-like song, the wood thrush gives only one call, a rapid pip-pip-pip.

Researchers interested in learning about whether wood thrushes could distinguish the songs of other wood thrushes nesting close by tape-recorded songs of thrushes in a study area. They carefully observed the responses of banded male thrushes that had established nesting territories to the songs of neighboring males. When the birds they were observing heard the songs of neighbors on the tapes, they responded by moving around a bit and singing. That was an effort to remind their neighbors that there was a boundary they should not cross. The banded birds did not seem particularly agitated or aggressive. They had already worked out a treaty of sorts.

Next, the researchers recorded the songs of wood thrushes from some distance away. When they returned to their study area, they played tapes of “stranger” wood thrushes. The responses of the banded birds on the study area were dramatic. The banded birds became agitated and spent a great deal of time flying around their established territories, singing and searching for the interlopers. They apparently recognized the recorded songs as different from the ones they heard regularly from neighboring male thrushes. The researchers concluded that wood thrushes were able to recognize and respond differently to the voices and songs of birds with which they were familiar and those of potential invaders that might threaten their individual territories. Compared to a turkey’s expansive social network, the thrush’s is rather small: its mate and immediate neighbors.

It is helpful for turkey hunters to master several calling devices and types of calls because turkeys are so skilled at recognizing one another by voice and have a complex vocabulary. But, as pointed out at the beginning of this story, some days turkeys won’t respond to any call. That is probably not a reflection of your calling skills, but more likely due to the individual turkey’s mood or motivation. Like people, some days you feel like singing and some days you don’t! In any case, do not limit the variety of calls you try. Look into new options and calling devices that are less frequently used, such as wingbones, trumpet calls, scratch boxes and tube calls. Who knows, sounding like a new hen in the neighborhood could bring that gobbler closer out of curiosity.

— Bill Healy, Ph.D., contributed to this article.