Evaluating Purple Martin Breeding Attempts at New Sites
Purple Martin Preservation Alliance
We at the PMPA believe that the key to the recovery of martin populations lies in the establishment of new colonies. We are committed to the study of breeding attempts at unestablished sites, in hopes that they may shed light on the dynamics of new-colony establishment. What follows is a list of breeding attempts by single pairs at potentially new colony sites. We take note of the location of breeding attempt, site characteristics, type of cavity bred in, age of parents, breeding success or failure, other martin activity at site, closest known colony, activity during following season, and other potentially significant information.
Natrona Heights, PA, 1999: Suburban backyard adjacent to wooded area 1/3rd mile from Allegheny River. One (unbanded) SY pair laid 4 eggs in natural gourd hung under T-14. First set of 4 eggs disappear. Second clutch of 4 eggs all hatched. Nestlings found dead at 4-5 days old, covered with blowfly larvae. Many additional SY-M's in residence - as many as three at one point, although only one resided continuously. Nearest established colony 8 miles north on Golf Course. No breeding activity the following year.
Butler, PA, 2002: Rural backyard with large pond adjacent to farm fields. One (unbanded) SY pair nested in natural gourd. Successfully fledged three nestlings. No nesting attempts the following year. Closest colony site only 200 yards away (Duke Snyder). Interestingly, neither SY parent was from the adjacent Snyder colony (where all nestlings were banded the previous season)
Butler, PA, 2004: Rural backyard with large pond adjacent to farm fields. One SY pair nested in medium to small sized natural gourd hung under an aluminum house. Eggs never hatched. SY-M (banded) was from Saxon Golf Course colony 15 miles SE. Closest colony site only 200 yards away (Duke Snyder). Interestingly, neither SY parent was from the adjacent Snyder colony (where all nestlings were banded the previous season). Landlord said he turned off the dawnsong when the pair first investigated the site because the female seemed "overly-excited" and kept "fussing" near the ASY-M decoy until he stopped the dawnsong.
Smicksburg, PA, 2004: Rural farming area. One unbanded SY pair nested in T-14 compartment with crescent entrance. Tall trees fairly close to T-14. Also, martin house sits in a depression next to road, making exit from martin housing almost level with road. Four egg clutch hatched on June 29th. By July 13th, only one nestling (debilitated) survives. Banded. Other remaining nestling dead. Many blowfly larvae in bottom of nestbowl. Nest replaced. Last nestling dies several days later.
Punxsutawney, PA, 2004: Rural farming area. One SY pair nested in round-holed plastic 10" gourd hung under wooden house. Housing was fairly close to road, barn, and house. SY-M was banded as nestling in 2003 at Zeglin Dairy Farm colony, 53 miles south. Only one 14 day old nestling as of 7/13/05. Very healthy. Banded. Two other banded SY-M also in residence that day. One from Saxon Golf Course colony site, 35 miles WSW, and the other also from Zeglin Dairy Farm.
Portersville, PA, 2003: Rural area. Large field next to house,
surrounded by wooded area. One unbanded SY pair nested in 10" plastic gourd on
rack. Also T-14 and aluminum houses available. Successfully fledge 2 nestlings.
No nesting activity during the following season. Nearest colony site (40 pairs)
only 3 miles SE at Moraine State Park, with huge sprawling lake. Seven
additional colonies within 5-10 miles.
Fombell, PA, 1999, 2000: Rural area. Backyard overlooking large open hillside adjacent to a wooded area. One ASY pair fledged four young in a natural gourd. The following year, one ASY pair fledged four young in a 10" plastic gourd on a different gourd rack. Many visitors, but no breeding pairs in 2002. Two colonies within 5 miles. Many large colonies within ten miles.
Greenville, PA, 2003: Rural farming area, but with fair amount of development in immediate area. One unbanded SY pair nested in round-holed 6"x6" compartment of aluminum house. Large plastic and natural gourds were also available, as well as wooden T-14. Successfully fledged 2 nestlings. No breeding activity the following year.
None of these breeding attempts resulted in the establishment of a new colony, but what conclusions, if any, regarding martin attraction and colony establishment can we draw from the examination of these breeding attempts?
1. It's probably a good idea to offer multiple types of housing, since you never know what they will prefer. The martins nesting in Greenville, PA chose a small aluminum compartment when both a wooden house and large natural gourds (usually considered superior for attracting martins) were present.
2. The martins that nest at a new site are not necessarily from the closest established colony site. The Butler, PA, 2004 SY pair was located only 200 yards from the large, established, Duke Snyder colony, but consisted of an SY-M that fledged from a colony over 15 miles away, and a female that did not fledge from the Snyder colony (because all nestlings were banded at the Snyder colony in 2003)
3. Vigilance is of the utmost importance when it comes to monitoring SY pairs. Two of the breeding attempts failed because of blowfly infestation that could have been prevented if nest checks had been done every other day.
4. Lastly, and unfortunately, as many disappointed landlords have learned, the attraction of one breeding pair is no guarantee of colony-establishment success, even if if this pair breeds successfully.