The last purple martin fledged from my martin colony on August 6, but Bob my neighbor and I still have around 15 martins coming to roost in our colonies. Last evening, August 11, a group of martins including several females with their largely independent young came in to roost. I suspect that this roosting behavior will end shortly as this is the latest we have had martins.
The 2015 martin season was one of the worst relative to weather issues. Cold rainy/snowy weather in late February and early March killed a number of the first martins that arrived and even more disastrous cool rainy weather during the first two weeks of May killed many nestlings. The nasty weather eliminated flying insects and the martins had little to eat. I tried supplemental feeding several times but most of the martins would not eat the crickets/scrambled eggs.
Fortunately nearly all the martins that lost nestlings successfully re-nested though brood sizes were smaller in many cases. I saw more twos and threes than fours and fives in the nests.
This year I erected 404 cavities: 80 aluminum Trendsetter rooms and 324 plastic gourds. I have five Trendsetters: three 12 room houses, one 16 room house and one 28 room system. I have 324 plastic gourds including Troyer Horizontals with cling plates and with tunnels/porches, Troyer Verticals, Excluders and Super Gourds. All cavities have round holes and I plan to continue using these entrances in 2016.
I had a difficult time trying to determine the “exact” number of pairs of martins due to the re-nests and just plain large number of martins in my colony. However, I went back and reviewed all my observation notes and selective nest checks and came up with a reasonably accurate number: about 365 pairs.
The Trendsetters housed 61 pairs out of 80 cavities and the gourds had 304 pairs out of 324. The Trendsetter occupancy level was 76% and the occupancy level for the gourds was 94%. The gourds tend to have higher occupancy levels probably because nest domination issues are not as great. Martins nest in colonies but they are territorial and will defend multiple cavities at times. Gourds provide martins with more territorial privacy than houses since gourds are spaced farther apart and the gourds can be arranged where the holes are not side by side by side or face one another. The 12 and 16 room Trendsetters have staggered entrance holes and seem to provide more territorial privacy than the larger 28 compartment Trendsetter which has holes side by side and holes that are vertically stacked; the 28 room system does have porch dividers. I observed more nest domination problems in the 28 room Trendsetter than the smaller Trendsetters.
My 2015 colony consisted of five Trendsetters and 12 gourd racks. I used one 36 gourd Super System, one 24 gourd Super System, two 24 gourd Geminis, and eight 24 gourd K systems. There were 24 gourds suspended from three of the Trendsetters.
I didn’t determine egg/nestling numbers but I believe at least three babies on average fledged from each successful nest and there were nests with more and with less. The bad weather no doubt adversely impacted egg clutch/brood sizes. So I believe well over a 1000 youngsters fledged from my colony but not all would survive during those first days outside the nest. Death from the skies took the lives of many of the martin fledglings.
Competition from house sparrows and starlings was minimal and these pests were eliminated by trapping and shooting. Not a single martin egg or nestling was harmed by any sparrow or starling. I have had my northwest Louisiana martin colony since 2005 and sparrows and starlings have NEVER harmed any martins in my colony or my neighbor Bob’s site. There are landlords who can successfully control these pests via trapping/shooting.
The worst enemy of small featherless martin nestlings in our colonies continues to be the bachelor SY male martin that is looking for territory and a mate. These SY males have killed untold numbers of small martin nestlings over the years and I have seen them carry out tiny baby martins and drop them in nearby hayfields: infanticide. Unfortunately, the single SY male martin is MUCH WORSE than any sparrow or starling in our two colonies!
I have managed to mitigate the SY male infanticide behavior somewhat by erecting several houses/gourd racks in April when the main influx of SY martins arrives in our area. The SY males can establish territory in these new systems rather than try to usurp active ASY martin nests. However, this approach doesn’t always work and the SY males that arrive in May are the main culprits in committing infanticide. Some single SY males are simply attracted to active martin nests since there is a female there and the males want the territory and her. Large martin colonies probably have more SY male problems since these colonies have an abundance of females and cavities. For 2016, I am thinking about keeping some cavities closed off until May to see if this will minimize infanticide behavior by later arriving SY male martins.
Once the martins fledged their young a more deadly enemy arrived and multiple killers struck. Several resident Cooper’s hawks started catching the martin fledglings as soon as the first ones were assembled in the tops of trees or on utility lines or just flying around the area. I observed the first kills during the last week of May and it continued until the last babies fledged during the first week of August. Large numbers of fledglings were caught during June and both male and female Cooper’s hawks were active in the predation. The recent fledglings have almost NO chance of escape when one of these hawks is attacking and often the hawks would simply pluck the martins out of tree tops or from utility lines. Many fledglings didn’t even try to fly but remained still and were easily caught. Any recent fledgling that did fly was caught within seconds.
Parent martins often assemble their fledglings in OPEN areas where the parents can easily feed their babies and see approaching danger. Martins are swallows with long pointed wings and usually fly/feed in open areas. Unfortunately, such areas are EASILY seen by Cooper’s hawks or other raptors. Plus SY males are often harassing the family group initially as the males try to attack and even copulate with fledglings; SY males are NO friends of martin fledglings. All this activity, including martin vocalizations attracts hawks.
A most deadly mature male Cooper’s hawk would come from the east way up in the sky and the adult martins would emit blood curdling screams of terror as they climbed up to meet the enemy. I watched in amazement as maybe 100+ adult martins were streaking through the sky like fighter planes as they assembled above the hawk and started their HOPELESS mobbing attacks. The hawk ignored the adult martins as he looked for “easy meat” sitting in trees or on utility lines. As soon as he spotted a helpless martin fledgling in the open, he would fold his wings against his sides and drop from the sky like a bullet, sometimes at a 90 degree angle straight down. The screams of terror coming from the adult martins were almost deafening but the martin fledglings stayed put and one waited for its death from the Grim Reaper.
There was NOTHING I could do but watch as these attacks were usually several hundred yards from our colonies. The hawk would simply grab the martin fledgling off the tree limb or utility line and disappear into nearby woodlots. Often there would be several martin fledglings clustered close together and incredibly in some cases the other fledglings never moved after the hawk snatched one of their siblings!
This male Cooper’s hawk caught NUMEROUS martin fledgling during June and July and a larger mature female hawk caught many, too. The female hawk hunted differently and she mainly made lower level attacks by flying over or through the tops of trees and grabbing vulnerable martin fledglings perched in the trees or on utility lines. Adult martins always saw this hawk before the actual attack and so did our resident scissor-tailed flycatchers and Eastern kingbirds. These tyrant flycatchers HATE Cooper’s hawks with a passion and the scissor-tails in particular savagely attack these raptors. The martins would form a huge screaming flock and circle the area where the hawk was at and follow her everywhere she flew. Any opening they had, the martins would dive down and mob her and she ignored them. I believe there were other Cooper’s hawks hunting the martin fledglings, including juvenile hawks which could have been the young of the mature hawks.
We probably lost 100+ martin fledglings to the hawks this season and the most I saw caught in one day this season were three. Martin fledglings were predated by the hawks almost daily during June and July. So we possibly had about a 10% predation rate on martin fledglings by Cooper’s hawks, which is probably not that significant considering the total number of fledglings in our colonies.
All of our housing systems are protected from rat snakes with net traps made from bird netting. This season I caught one HUGE black rat snake during the night or early morning in a trap. If this snake had made it up the pole, he/she would have inflicted massive damage to the martins in those gourds. I removed the snake and the snake got a new home a few miles down the road from our colonies. We don’t kill rat snakes caught in our net traps as snakes are important members of the ecosystem and they do eat rats though I have never seen one do so! I have only seen rat snakes eat birds so a better name for these snakes may be rat and bird snake! Bob didn’t catch any snakes this season and rat snakes seem to be declining in population in our area.
Every season we have problems with great horned and/or barred owls catching martins that roost out in the open on house porches/gourd racks or male martins that come out on porches to dawn sing. This season a great horned owl did catch some martins that unwisely roosted in the open. I tried to frighten off any martins that roosted in the open but there were always some martins that I missed or returned back and I would find plucked martin feathers under nearby trees or around fence posts. I also got up every morning around 4:00 am and patrolled through our colonies when the male martins were most actively dawn singing. This action on my part helped a lot to keep the owls from attacking these martins. “Our” owls hunt “like hawks”; that is, they catch martins sitting in the open on porches or gourd racks during the night or early morning darkness. The martin losses were not large since I managed to chase most martins that tried to roost in the open off the housing. Either I could do it or the owls would be more than happy to do it for me and kill several martins in the process!
I supplied both eggs shells and oyster shells for the martins and their nestlings. I observed a definite preference for egg shells and the martins would be in a “feeding frenzy” when I scattered eggs shells in my driveway near the martin colony. The martins did eat and feed the oyster shells to their young but there was no feeding frenzy! I have already started saving egg shells for the 2016 martin season.
We had abundant rain through the winter and spring and there was abundant mud for the females to use in building mud dams in their nests. Though all my cavities have pre-nests of pine straw, the martins did add oak leaves, twigs, grass stems and mud to their nests. Some females built elaborate mud dams in their cavities and I saw dams in both gourds and house compartments. None of these dams were at the entrances but were farther back to create a smaller and more compact area for the nest bowl containing the eggs/nestlings. The mud dam helps keep the eggs/nestlings together and may make it easier for the female to incubate/brood. Mud dams also may function as a protective barrier and “hide” the martins from predators looking inside a nest cavity and give incubating/brooding females a sense security. I like mud dams!
I am still thinking about possible changes for the upcoming 2016 but nothing definite at this time. Bob and I will be making changes to some of our satellite martin colonies for 2016. Bob has built some new aluminum houses to replace some older ones and we hope to use more nest trays in our houses. So there will be plenty of martin relative activity to keep us busy until next year.
Photos Of My Martin Colony
Here are two current photos showing my empty martin colony! We have had triple digit temperatures for about four weeks it seems and everything is burning up! No rain for over a month.
One Martinless Section
Second Martinless Section
Here are some photos from this year showing my martin colony with martins! These photos have been posted on the Forum earlier in the season.
Swarm Photo
Another Swarm Photo
Martins Stressed During Bad Weather; Perched On 28 Room Trendsetter
One Section With Martins
Another Section With Martins
Another Section With Martins
Entire Colony On Misty Morning
My Favorite Trendsetter; 16 Room House
Steve
