Introducing the Purple Martin Dawnsong Tape
Reprinted from: Purple Martin Update 3(1)
|The PMCA's innovative new Purple Martin dawnsong tape. This tape is highly successful in attracting Purple Martins to potential colony sites. It contains 60 minutes of loud, uninterrupted, Purple Martin dawnsong, the nocturnal song that adult males sing to attract subadults.|
Purple Martin Dawnsong
The Purple Martin Conservation Association is excited to announce the availability of the most unique accessory yet developed for attracting martins: a 60-minute cassette of Purple Martin Dawnsong. Dawnsong is the unique set of vocalizations that adult (ASY = "after-second-year") male martins emit during the predawn hours of spring while flying high above their colony sites or while perched nearby. It is a loud, continuous series of chirps presented in a syncopated series of about seven to nine notes repeated over and over. Its function is the attraction of nocturnally-migrating subadult (SY = "second year" or yearling) martins to a singing male's colony site.
Dawnsinging is not a group chorus. Each male flies his own path in slow, wide circles about 500 feet up, singing his own unique song. It is estimated that the sounds from a morning of dawnsong project across at least 30 square miles of ground and perhaps 100 cubic miles of air, as early morning acoustics are the best for sound transmission.
By attracting more colony members, a dawn-singing male is attempting to leave more offspring during a single summer's breeding effort by increasing his opportunity of engaging in forced extrapair copulation with the mates of the subadult males he attracts. Since the migration of subadults lags behind that of the earliest adults by at least 4-6 weeks, adult males don't begin their dawnsinging until about the time that subadults begin migrating through their area.
Advantages of this Tape Over Others
This tape contains 30 minutes of uninterrupted dawnsong on each side for a total of 60 minutes of playing time - there is no human narration. Because this tape is specially designed for being played outdoors for martin attraction, it can be played extremely loudly without distortion. And because it contains martin dawnsong, it will attract any migrating martin within earshot.
Who Should Use the Tape
The dawnsong tape is designed for use by persons trying to attract martins to new sites. There is no need to play the tape if you already have an active martin colony. In addition, if you have been unsuccessful in your attempts to attract martins in the past, the J-card liner of the cassette contains the article: "The Top Ten Reasons Why People Fail to Attract Purple Martins," reprinted from the Purple Martin Update 2(3):28-29, 1990. If you are making any of the mistakes listed there, the martins you attract with this tape will probably just move on after a few hours. The J-card packed with the cassette also contains instructions on how and when to play the tape for best results.
When to Use the Dawnsong Tape
This tape works best if played during the predawn hours when adult males normally sing their dawnsong (i.e., between 4:00 - 6:00 a.m., in the darkness preceding dawn). And it will only attract migrating martins if played during the correct season when adult male martins normally sing their dawnsong at your particular latitude (don't confuse martin 'dawnsong' with the common day-time chatter that is so typical of an active martin colony.) In other words, this tape will only work during the time window when subadult martins are migrating through your area. Playing this tape during the 4-6 week time window when adult martins migrate through your area will be relatively non-productive since adult martins tend to nest only where they nested previously, due to their strong site fidelity. It is rare for them to nest anywhere else (although this tape may lure them down to use your housing as an overnight "motel" on their way north to their previous breeding sites).
To determine the correct time window for playing this tape in your area, refer to the Purple Martin Migration-timing Map printed below. You should begin playing this tape about 4-6 weeks after the first adult martins normally begin arriving in your area (i.e., 4-6 weeks after the dates shown on this map). And since the migration of subadults lasts about 4-6 weeks in the northern half of the range and 8-10 weeks in the southern half, there is a very broad time window in which to play the tape. For example: if you live somewhere along the April 1st line shown on the map below, you can begin playing the dawnsong tape as early as May 1st and can continue playing it as late as June 15th. If you live near the February 1st line, you can begin playing the tape as early as March 1st and can continue playing it as late as May 15th.
How to Play the Dawnsong Tape
For best results, this tape should be played as loud as possible without distortion, with the speaker(s) aimed skyward from the general vicinity of your martin housing. Portable "boom boxes" or home stereo speakers work best. Since the tape must be played in the darkness of early morning, you may want to partially wrap your cassette player in plastic to protect it from the condensation of morning dew or drizzle. Since the tape has 30-minutes of uninterrupted martin singing on each side, you will have to flip the tape over after 30 minutes, unless you have an auto-reverse system. The more you play this tape between the hours of 4:00 - 6:00 a.m., and the more consecutive mornings, the better your chances of attracting migrant subadults. Clever persons can hook their machines up to automatic timers so that the tape comes on by itself at a predetermined time, but be careful handling electrical appliances while standing in dewy grass.
Once several martins have been attracted and begin spending the night at your housing, you can cease playing the tape altogether during predawn. Since playing a "boom box" loudly, outdoors, in the middle of the night may disturb your neighbors, you might want to discuss your plans with them ahead of time.
How the Dawnsong Tape was Made
The dawnsong material from which these tapes were made was recorded in Severna Park, MD during 1989 by Dr. Eugene S. Morton of the Smithsonian Institution in Washington, D.C. Dr. Morton is a leading martin authority and used the most sophisticated recording equipment available - a Nagra reel-to-reel tape recorder with a Dan Gibson parabolic microphone. Dr. Morton, who serves on the scientific advisory board of the PMCA, generously donated the use of his master tapes.
To assure absolutely the highest sound reproduction possible, we had the tapes duplicated in "real time" directly from the master tapes by the Library of Natural Sounds, Cornell Laboratory of Ornithology, perhaps the finest bird recording facility in the world. The project was sponsored by the Purple Martin Conservation Association and proceeds from the sale of the tapes help fund the research, conservation, and educational projects of the organization.
|Purple Martin Migration-timing Map. The gray background shows the breeding range of the Purple Martin north of Mexico. The horizontal lines mark the average first-arrival dates of adult martins at long-established breeding sites. Landlords with younger or smaller colonies typically experience slightly later return dates. Yearling martins (i.e., subadults), the only age group that will typically colonize new breeding sites, don't begin arriving until about 4-6 weeks after the earliest adults do and they continue arriving for an additional 4-6 weeks in the northern half of the breeding range, 8-10 weeks in the southern half. It is only during this later time period that this dawnsong tape will attract martins looking for sites to colonize. This is because most adults aren't looking for breeding sites while they migrate, they are merely on their way back to their former breeding sites. Typically, adult martins only switch breeding sites if they experienced reproductive failure the previous season, or if their colony site has deteriorated.|
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