Purple martins emit a limited number of mostly unmelodic but loud vocalizations in response to specific behavioral stimuli. These calls often consist of a few loud throaty chirps with a limited vocal range and are repeated over and over again. Most martin vocalizations are largely related to territory establishment, mate attraction, other martin recognition, predator/alarm warnings, distress situations, and recognition/feeding of young. Purple martins are swallows and swallows in general have limited song richness and variety. You do not see the incredible diversity that is characteristic of such masters of song as the mockingbird.
Since martins are nomadic, birds of the open skies, and colonial nesters, they do not defend a large nesting territory like that of most songbirds. Therefore, perhaps a rich, variable vocal style did not evolve. Many male songbirds advertise their territorial rights through song. These songs warn other males to keep away and also attract mates. From a biological perspective, it is better to chase other males away by non-physical techniques like vocalizations rather than direct attacks that could end in injury or even death. Martins’ territorial domains can often be measured in inches. Male martins do not need an extensive “song vocabulary” to protect their territory from other males. Martins are much more prone to use physical force, when necessary, to defend their small territory from other martins rather than use territorial vocalizations.
Over the years I have tried to differentiate the various martin vocalizations by associating their calls with specific martin behavior. Of course, it is difficult, almost impossible, to capture the actual sound in words when you are trying to describe the vocalizations. Some of the calls just seem to defy the written word! How to do you find the words that truly capture the sound and therefore really mean something? Not easy.
The Male Martin Is More Melodic, Emits More Varied Calls, Is Louder, And Calls The Most
There is at least one melodic martin call and the male martin emits it. The male also calls the most and tends to be louder in his vocalization style. This is typical of songbirds and the males do most of the singing and calling as their vocalizations relate to territoriality and mate selection. The liquid, bubbly, gurgling call that ends in the "kriek" sound is the signature call of the male martin. Along with behavior and plumage differences, this gurgling call is a good way of distinguishing between immature (SY) male and female martins. Males make this call day and night. I have often heard the rich, bubbly call of the male at night and this call may be a "nocturnal serenade" to his mate. It also could be in response to other males emitting the same call. You may have a chorus of males "showing off and telling other males" that this is "my territory and my mate". Males also make this call while flying over-head and while around their nest sites. It may also relate to territory establishment/protection. Unfortunately, the male’s nocturnal song can be his vocal "death warrant". Owls have no difficulty picking up these nightly calls and such calls can be a "food magnet" for hunting owls.
A male martin also emits a seductive, cooing call when trying to entice a potential mate to enter a gourd/house compartment with him. It sounds something like "che...che...che" repeated softly and continuously as the female enters the nest site with the male inside. It is somewhat like a version of the young martins' food begging call, "choo...choo...choo..." repeated over and over. The male martin seems to be almost "begging" the female in his most tender vocals to accept him and his territory. It does NOT work every time. Furthermore, the adult (ASY) male martin makes the "dawn song" vocalization in the early morning hours, usually between 4:00 am to 6:00 am, to attract migrating female martins. This is a loud unmelodic call of a continuous series of a few notes which seems to be variation of the basic "Here I am" call that goes something like "chew...wew...chew...wew...chew...wew". The male makes this call continuously and I have often heard the males calling high up in the early morning sky. The early morning acoustics are excellent and the call can be heard for a long distance.
Calls Of Both Male And Female Martins
Basic "Here I Am" Call The most common vocalization made mostly by male and to a lesser extent by the female is an unmelodic throaty call of several loud notes repeated over and over. Most martin landlords know it well. This is the call we hear when the martins first arrive at their nest sites and seem to be telling us, "Here I am! Now where is my house/gourd?" Many times I have rushed outside on cold January days when the first martin lets me know he (usually) has arrived. And some times I have been royally fooled by the master mimic of all, the male mockingbird! Mockingbirds have mastered this basic martin call with perfection. I have tried to find the words that may come close to the actually sound. It seems to be a throaty, rich "chew...wew...chew...wew...chew...wew ", repeated over and over again as the martins fly overhead. Male martins make this call in particular when they see other martins in the distance; the males seem to be advertising their "property". These males call loudly and often fly to the other martins and may try to bring them down to the nest site. In this case, the "Here I am" vocalization may be used to attract other martins. This vocalization may be a martin recognition call.
Danger/Alarm Call Both male and female martins emit the well-known basic alarm call in response to a predator or potential predator. It is a very loud call in machine-gun fashion, something like "da...da...da..." repeated over and over again. Such a call produces widespread panic in the martin colony and all the martins disburse and head for the safety of the open sky or directly for the "enemy". This alarm call becomes exceedingly intense when parent martins with nest bound or flying young see a predatory bird approaching. When a huge flock of alarmed martins is screaming the danger call in unison, it is indeed an awesome sound.
Mobbing Call The mobbing call that martins emit when attacking a predator, such as a flying hawk or crow or even a human or cat, is identical between male and female, though the male does most of the mobbing. It consists of a loud, raspy, "acccck..." cry as the martin dives on the predator and passes within a few inches or feet of the enemy; martins do not strike the predator. It lasts just a second or two and appears to be raspy single note call. Sometimes martins emit the basic alarm and the mobbing call intermittently as the martins attack predatory birds, like Accipiter hawks.
Distress Call/Death Rattle Both male and female martins make the same distress call when they are losing a battle with another martin or starling, usually inside the nest cavity, or have been captured by a hawk or an owl. In the competition situation, the call may be the basic alarm vocalization, "da...da...da...", mentioned previously or a persistent scream that goes something like, "annnnk...annnnk...annnnk....". This call is repeated over and over again until the losing martin escapes. The most distressful call, the "death rattle", is this same "annnnk...annnnk...annnnk..." cry that a martin emits when captured by a hawk, owl or other predator. However, in the predation situation, the cry is very loud for a short time, just seconds usually, until the martin succumbs. I have heard these "death rattles" when martins are taken by Accipiter hawks during the day and by barred owls at night. The night cries of martins being captured by owls can be terrifyingly loud and these screams have awakened me.
Young Martin Calls Inside and Outside The Nest; Recognition Calls By Parent/Young Martins
While baby martins are still in their nests, they emit a redundant feeding vocalization. Their feeding call goes something like "choo...choo...choo..." that is repeated continuously and rapidly upon the approach of the parents. It is a food "begging" call. As mentioned previously, it is interesting that the seductive cooing call of the male martin, "che...che...che...", that he emits when a female enters the nest with him, is somewhat related in sound to this food "begging" vocalization. It is as if he is "begging" her to stay with him and become his mate.
When baby martins are fledging, both male and female parent martins emit a similar call that may assist in establishing a recognition bond between parents and young during the young martins’ maiden flight. As the babies leave their nest, both parents fly with the young and there is an interchange of vocalizations. These vocalizations seem to be related in style and sound to the basic feeding "choo...choo...choo..." call. However, these recognition vocalizations do not appear to be vocalized as rapidly as the feeding call. There also may be a difference in the tone of this "choo...choo...choo..." call between parent and young. This vocalization may help establish that very important first recognition bond between the parent martins and their young outside the nest and allows the parents to keep track of their babies.
While the parent martins are teaching their young to hunt for food and develop flying skills, both parent and young continue to call to one another with the similar "choo...choo...choo..." vocalizations. Again, this call may be a recognition call and helps keeps the family unit together. This vocalization is particularly evident when the parent martins bring their young back to roost in their natal nests. In my large colonies, I could often hear a multitude of "choo...choo...choo..." calls as numerous martin families were in the air at the same time and all bringing their young back to roost in the gourds/houses. Martins, both adult and young, may be able to discern differences in this basic call to differentiate between various flying family units. The parent martins seemed to recognize their young from all the other young that were airborne simultaneously. Purple martin young that are close to fledging or have fledged make a distress call that sounds like the adult martins’ cry, a persistent "annnnk...annnnk...annnnk…" scream. They make this cry when caught by predators or sometimes when humans pick them up. The parent martins usually emit the loud alarm cry, "da...da...da...", and often respond by mobbing the predator, such as an Accipiter hawk or even a human who has picked up the baby. Babies’ distress calls warn the parent martins that the young are under attack or are threatened.
Purple Martins Are Loud, But Not Very Melodic
Purple martins are very vocal birds, but not very melodic. The male martin is by far the most vocal in style and loudness; he also calls far more often than the female. With the exception of the liquid, bubbly call of the male, most martin vocalizations consist of a few loud throaty chirps strung together and often repeated over and over again. As in all songbirds, martin calls relate to specific behaviors such as territory establishment, mating, other martin recognition, anti-predator responses, young/parent recognition, and distress situations. Martin vocalizations seem to maximize loudness and repetition and minimize richness and variety. This vocalization style is biological adaptive to such colonial, nomadic species as purple martins that do not defend large nesting/feeding territories and spend considerable time together patrolling the open skies. Loudness and repetition are effective vocalization styles in such species as purple martins.
