Preliminary Purple Martin Report For 2005

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Steve Kroenke
Posts: 4321
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Preliminary Purple Martin Report For 2005

Postby Steve Kroenke » Fri Jul 08, 2005 10:05 am

Preliminary Purple Martin Report For 2005

Though the martin breeding season is almost over in northwest Louisiana, my colony site is a bustling social center for hundreds of martins during the early morning until sometime in the afternoon each day. I believe both Bob?s colony and mine have had over 500 martins visiting on some days though the numbers are declining as we get into July. These are primarily ASY and SY martins with some ?independent? fledglings. My gourd racks and particularly my Lone Star Goliad house will be covered with martins. It appears our colony sites are the main congregation point for martins in our immediate area. When the martins bolt from the housing, the sky is almost black with them it seems. However, very soon most of these martins will be leaving, particularly when all the remaining pairs have finally fledged their young. Many of the visiting martins try to enter the nests of these pairs and the parents vigorously chase them away.

I still have a few pairs of martins with young and nearly all these will fledge in the next few days. Some have fledged a few of their young while several babies are still in the nests. There is a late SY pair nesting in one of my vertically deep woodpecker gourds and I believe they will fledge around July 20.

It has been an incredible and fantastic martin season at my new colony site in northwest Louisiana. I have studied martin biology and behavior for over 40 years and I have never seen anything like what has happened at my colony this first season. Though I will be presenting a comprehensive status report on my colony when the last pair has fledged their young, I attracted an amazing 81 pairs of martins this first season! This includes 28 ASY pairs and 53 SYs. Of these, 76 raised or are finishing raising their nest bound young and the total number of fledglings so far is well over 300. Five late SY pairs did not complete the breeding cycle though they were pair bonded, carried leaves to their nests and some females even laid eggs. However, they were still bonded to the site and hopefully will return next season as more reliable ASYs.

The number one problem has been predation and it is significant. In the winter and spring months, we are deluged with migratory Accipiters and merlins which make multiple passes over our colonies daily and attack often. I even saw several peregrine falcons, two of which made unsuccessful low level attacks on martins above the colonies. After the martins fledge their young, the resident Cooper?s hawks start predating large numbers of these vulnerable fledglings, sometimes as many as five a day. Our first hawk attacks started almost exactly when the first martin pairs fledged their young. The hawks primarily hunt the martin fledglings at their family assembly sites in tree canopies, on dead tree limbs, or on utility lines and I have observed numerous attacks. These were nesting hawks and I believe their nest is a mile or two directly west/northwest of our colonies in a deep woodlot as I watched both the small male and larger female carrying caught fledgling martins to this area. I estimate we will lose over 100 fledglings to the Cooper?s hawks by the time the last martins are fledged. Since we have around 1000 fledglings produced by about 250 martin pairs in our colonies, this represents around a 10% mortality rate from Cooper?s hawks. This predation time frame will be from the first week in June through mid-July. The hawk attacks have been declining since the beginning of July as fewer martin fledglings are available for hunting. Though the parent martins vigorously mob the hawks, the hawks are not deterred and totally ignore the martins that are attacking. I will sometimes see one of the hawks being following by dozens of screaming and attacking martins and the hawk just lazily flies around looking for a vulnerable fledgling.

Great horned owls slaughtered numerous martin fledglings that were roosting on exposed gourd crossbars or house roofs/perches. This type of roosting behavior is extremely maladaptive in areas where either great horned or barred owls are hunting. I found kill after kill scattered about our yards. The owl will take the fledgling to the ground, particularly on a closely mowed lawn, and usually within 50 feet of the martin housing. There the owl butchers the youngster. All you will find are plucked martin feathers and occasionally a great horned owl feather mixed in. The owls lost many feathers during their nightly reign of terror! At Bob?s colony, the owls even broke down perches on his T-14s when grabbing roosting fledglings. After the owls had killed between 20 and 30 fledglings, the martins quit roosting outside. The ones that roost inside their nests have been safe.

I have been amazed that not a single rat snake has been caught in our net traps! Bob caught a number of snakes last season and took them about a mile down the road and released the serpents. I was sure we would have caught some snakes by now, but none so far.

Starlings and house sparrows are of little problem in our colonies so far. I shot two starlings this year and neither one was at my colony. Starlings are in the area but they have been largely a non-issue for me and I have had little concern about them this season. Of course, this can change for subsequent years. If they choose to try to nest in my housing, they will be destroyed. Simple as that! One male house sparrow showed up at Bob?s bird feeders in early May and I spent an entire day chasing him with my pellet gun! I never shot him, but he fled the area by the end of the day and never came back.

My colony has been parasite free due to 5% Sevin dust. I have used Sevin to control martin parasites since the late 60s and it is an outstanding mite eradicator. I use Sevin as a preventative measure at the beginning of the season and will use it as necessary later if I see any mites/parasites. But I rarely see any, particularly in my natural gourds because the Sevin is more easily applied to the inside gourd substrate. The Sevin permeates the crevices and internal gourd membranes and remains viable for much longer than on plastic/aluminum surfaces. I simply sprinkle about half a teaspoon (you can use less if you choose) of Sevin in a natural gourd, shake it up real good to coat the inside all over, add my pre-built nest of pine needles/oak leaves, and then hang the gourd. Most of my natural gourds are vertically/horizontally deep which minimizes rainwater infiltration, so the Sevin is not often moistened. This keeps the Sevin viable for much longer. For my plastic Super Gourds, I sprinkle the Sevin in the pre-built nests and then check for mites later in the season. I do the same with my aluminum martin houses. If I see mites, I then sprinkle more Sevin in the nesting material.

I hope to visit Shreveport in August to see if the gigantic pre-migratory martin roost still exists at the Schumbert medical complex. Last year, this roost had around 100,000 martins and did create considerable controversy because of the martin fecal droppings and associated odor. I visited this roost last year and was awestruck by the numbers of martins and the powerful stench of their ?poop?!

My comprehensive status report will have detailed data relative to occupancy levels by housing types, number of fledglings, and other pertinent information, including my tentative martin housing plans for 2006. I will also re-post photos of martins using my natural gourd designs that maximize vertical/horizontal depth.

Hope everyone had a great martin season.

Steve

John Miller
Posts: 4756
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

Postby John Miller » Fri Jul 08, 2005 2:40 pm

Steve

We've all learned so very much from your writing about your experiences. I prattle off martin stuff all the time -- to anyone who cares to listen -- that's really based on your experience -- ha.

Thanks,
John Miller,
St. Louis

Steve Kroenke
Posts: 4321
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Postby Steve Kroenke » Fri Jul 08, 2005 2:57 pm

Hey John,

I appreciate that nice comment! I have learned a lot from other folks on this Forum, too. It seems I learn something new each season and I sometimes I have to re-evaluate my thinking on an aspect of martin biology or behavior. Martins continue to educate, entertain and amaze me every season. Martineering is a hobby I will never get tired of!

Hope you are having a great martin season.

Steve

Dick Sherry
Posts: 769
Joined: Wed Nov 12, 2003 5:30 pm
Location: Tulsa, OK

Postby Dick Sherry » Fri Jul 08, 2005 3:14 pm

Steve, I am glad you have had such a great season in your new location! You had so many bad things happening to your colony in Florida that some folks would have just given up. It was probably a hassle to relocate so far away, but it looks like you have found the "Promised Land" for a purple martin fan. Hope each year gets better and better, and the hawks find somewhere else to hunt.

Steve Kroenke
Posts: 4321
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Postby Steve Kroenke » Fri Jul 08, 2005 5:27 pm

Dick,

It has been a fantastic season in spite of the predation pressures from hawks and owls. My colony site is so open that most of the attacks on the adult martins fail. It is mainly the martin fledglings which bear the brunt of the predation. I can live with that.

This area in northwest Louisiana is the Promised Land for purple martins! I feel confident I can easily attract between 100 and 150 pairs of martins my second season if I erect sufficient housing.

The resident Cooper?s hawks are probably here to stay! However, I want to find their nest and that most revealing plucking post/perch which will yield the secrets of prey items. The male Cooper?s hawk hunts for himself, his mate and young during the breeding season. He carries prey to a plucking post located near the nest. The female retrieves the prey to feed the young. When the young are older, then the female starts hunting, too.

Hope you are having a great martin season.

Steve


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