Posts Tagged ‘predator guards’

Where Your Purple Martins Went

Sunday, June 20th, 2010

As the purple martin season for 2010 winds down in the Southern states and hope for wannabe landlord dwindles, I have heard some folks wondering where their purple martins went. Some established colonies have even reported the complete failure of their colonies to arrive at all. In this article by Cynthia Porter from the Winona Post she describes some landlords experience with colony loss. There was some speculation about “where the martins have gone” and I hope to add some clarity to that issue.

The article mentions specifically that the martins were, “stalled in April due to low pressure systems in the south. That delay seems to have upset normal migration patterns in which birds like purple martins send scout males first, followed later by females.”

I thought that I just had to clarify this statement that seems to speak to the age old (and false) myth that purple martins will send out “scouts” ahead of the rest of the colony. Purple martins experience a staggered molt in South America and  older birds will complete molting before younger birds do. The phenomenon known as “scouts” is actually just older more experienced birds rushing “home” to secure nesting prime nesting spots. Now that we have that straightened out…

As far as why YOUR purple martins never arrived; there is only really one reason.

The colony experienced losses of adult birds, nestlings and fledglings due to predation, weather extremes (cold or drought) greater than the rate of reproduction.

Here is how that can happen:

1. Prolonged Cold Spring Snaps

2.Extended Dry Weather / Drought

3. Predation

Let me go into detail on these:

In cold weather (temps of 40 degrees F or below) aerial insects are not available and starvation will occur within days. Record Low temps for record breaking extended periods of time, made foraging for food impossible for many purple martins. So birds that may have arrived early, didn’t survive this year. Purple Martin landlords often report of “early arrivers” braving intense spring cold snaps for days and even with poor weather forecast, martins will often times continue their journey Northward and remain at their colony site. Many landlords last year and this year reported huge losses of ASY (adult) purple martins from cold snaps such as these.

Droughts were widespread and severe in many areas in 2008 even more so in 2009. Reduced rain results in reduced amounts of aerial insects thus reducing available food supply. Large losses were reported last year of thousands of dead nestlings that starved to death. According to Louise Chambers of the Purple Martin Conservation Association, “.We don’t know if adults will return after total nesting failure” so even though “many landlords are reporting a very good season this year” it could be that those adults returned or their sites attracted new adults.

The most important factor and the one WE CAN DO SOMETHING ABOUT, is predation. Most predation goes undiscovered. Without safety precautions, such as predator guards in place, raccoons and snakes can easily climb ANY martin pole and go from martin nest to martin house for an easy meal. A colony can be decimated within days. Once a gang of raccoons finds the tasty treats (your birds) at the top of your purple martin pole, it will climb every pole in the neighborhood. And believe me, I have seen it Raccoons DO eat birds! Last year at our local roost, I witnessed raccoons dining at their leisure on so many purple martins that their body parts littered the ground like confetti. You can read the post here: Davie Fla Roost.

One of the reasons why the Purple Martin Conservation Association recommends nest checks is to discover problems early. By discovering problems such as nest predation, you can monitor the health and growth of your colony. Many landlords that report complete colony abandonment have in fact been suffering chronic losses and/or predation. The ultimate failure of many colonies could have been avoided by careful observation and having predator protection installed.

So to conclude, if you don’t observe your martins and perform nest checks, your colony may have suffered losses of adults from cold weather, losses of nestlings due to dry weather and, if unprotected, losses from ground predators as well. Then that is why you had no martins return at all.

If you are interested in reading more about raccoons and the threat they pose, try this article titled, “Raccoons in our Midst”.

If you want to know what other threats there are to your colony check out this surprisingly long list, “Threats.”

©2010 PurpleMartinArt.com / S.Halpin

Post Traumatic Snake Disorder

Wednesday, April 29th, 2009

A big thank you to those that emailed me about my recent snake attack. I should apologize to the snake that I vanquished to the City dump.

Like I told Dave J, I know better than to kill the snake. It was a case of projection- at anger towards myself. So much for “Don’t hate the player, hate the game.” I doubt I will now start killing every snake I see. I usually catch them and then hold them for my 2 kids to touch and squeal over. Also in retrospect, should have known the snake must have gone partway up that pole before, as the last time I did a check there were none of the small tree frogs that like to sleep under the guard during the day.

S&K predator guardRegarding the inadequate S&K predator guard on one of the last remnants of S&K at my site; I sprayed foam insulation into the openings on the adaptor to close the passageway the snake must have used. I also placed snake netting below. In the pic you can see the gap that is formed when the circular opening of the guard is attached to the triangular pole adaptor that is underneath. Not only is their a gap there but then there are several small openings that are part of the design of the adaptor itself. The adaptor is actually the same piece that is used as one of the older S&K gourd racks. When in use as a gourd rack the rods that the gourds are hung on go through these openings. When used as an adaptor for the guards, there is nothing to block these openings and a small snake can pass through. As my experience has shown a small snake can easily kill just as effectively as a large snake.

when used as a gourd rack

when used as a gourd rack

 The spray foam insulation seems to have closed off these openings and be an easy fix. Also snake netting is in place anyway. 

A big thanks to Bob n Jo in Iowa, for letting me place a link to their FREE Purple Martin Bird House on my other website, purplemartins-r-us.com. It is a 7 page PDF plans to construct chalet style houses out of insulation foam board. If any of you complete this project, I would love to hear about it.

©2009 Blog contents S.Halpin/PurpleMartinArt.com