Archive for June, 2011

Why Purple Martin Nestlings Jump

Sunday, June 26th, 2011

Our last blog post touched on one of the reasons that purple martin nestlings jump prematurely out of their nests. Referred to as “jumpers” these youngsters are often doomed. The reason why I,  along with many other South Florida landlords, have seen a huge increase in jumpers this year over previous is our record breaking drought conditions. Dry weather means fewer bugs which means purple martins go hungry and nesting success plummets.

The main reasons that martin landlords encounter jumpers are: parasites, extreme heat and hunger. Drought, though not a specific reason, contributes to low food supply and hunger/malnourishment.

Parasites can torment young inside a nest. Though some have argued that nature should be allowed to take its course, the natural instinct of the Purple Martin (Progne subis, subspecies: subis) has been altered by man.  Before Native Americans created the tradition shift in martins, the nest sites of these birds were tree snags and they nested farther apart. You can read about some of the 1/4 tsp in nesthistory of martins at our parent site: PurpleMartins-R-Us.com. They were much like their West coast cousins, Progne subis, subspecies: hesperia and subspecies: arbicola. The shift not only affected were they nested (tree snags vs man made houses) but the way they nested, as it is believed they were not as colonial in their nesting. That is to say, they were spaced further apart and did not nest in such large groups. The groups of martins nesting in close proximity can create parasite population explosion. We counter this by periodic nest changes and/or the use of a small amount of Sevin. We have a great link to a video on how to do a nest change.

Extreme heat in a nest can  be challenging to combat but if not associated with drought or food shortages, are usually easy to remediate. By making sure all vents are open in nest compartments and gourds, air circulation can be increased which can help lower temps. Many artificial gourds have vents that can opened as an option. For example Troyer gourds have built in mini vent canopies that can be drilled open easily. We recommend drilling these open before the season but a cordless drill can open those up quickly. If those are too small or you want larger vents (more air circulation) than a 1/4 inch threaded PVC elbow (90 degrees) is perfect for the job. It can  be easily installed on any gourd or house for that matter to increase air flow. Just drill a hole large enough to thread the end in and caulk in place. Make sure it points down and, if you want, attach a small piece of screen to cover the opening to allow air in but keep wasps out. The picture shows a modified gourd with elbow in place at the highest point which will push out the hot air as it rises. Know that in Northern climates you may have to plug these vents inn the early spring in times of cold weather to keep your martins warm.

Other tricks folks employ:

Using a frozen gel pack placed in an empty compartment. A frozen bottle of water can be used also.

A secondary shade can also help. Placing a sunshade to keep the sun from beating down on the house surface can decrease temps.

-------photo by OakleyOriginals on Flickr

Even a misting system has been used by many with success. Just makes sure the water does not go into compartments which would lead to wet nests. Also the misters should only run intermittently in the hottest part of the day so that the water can dry off. The evaporation is what cools. Don’t let the misters run at night or continuously. Our Free Purple Martin House Plans page has instructions available on how to make a mister system for your martin houses.

Hunger is a difficult problem and the debate is heated on how much humans should intervene on this. Though supplemental feeding is often done in early spring cold snaps for returning adults, one should strongly weigh the consequences of feeding purple martin nestlings. Remember that if you have several nests that are doing poorly from lack of food, the parents are suffering also. If there is a long term problem, supplemental feeding is a very short term solution. Read our Emergencies page for first responder care of purple martins.

What other problems lead to Purple Martin nestling Jumpers? Let us know what you think.

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(c)2011 www.PurpleMartins-R-Us.com

Drought and Heat Takes a Heavy Toll

Saturday, June 25th, 2011

Time after time, this season, I have received calls from landlords concerning dead purple martin nestlings. I myself have found several jumpers this season. Jumpers are nestlings that are far too young to fledge but jump out of their nests for whatever reason. Usually extreme heat, hunger or parasites are the culprits that lead a martin nestling to such a desperate act. I liken it to people trapped in a high rise that is ablaze. The victims jump to their death to escape the fire.

purple martin feederThis year South Florida is suffering from record drought conditions. In droughts flying bugs are significantly decreased leading to catastrophic food shortages. Nothing but rain can re-establish the equilibrium of the food chain. Since our weather is usually fair, our population of purple martins is not familiar with supplemental feedings. In some emergency situations like extreme cold, purple martins can be trained to accept food from an elevated tray or Bed & Breakfast type feeder. Unfortunately, when the weather is fair enough to fly and catch some bugs, the birds will just forage longer and farther from the nest. So training them to accept feedings is extremely difficult. To see a video of supplemental feeding of purple martins click here.

In the usual activity of a purple martin nest you will see some of the nestlings at the entrance waiting to be fed while others are sitting in the back of the nest resting. As the ones in front are continuously fed and get full they turn around and retreat to the back of the nest to sleep, digest and grow. The nestlings that were resting and digesting then get hungry again and come back to the front of the nest to take their place at the entrance to wait for a mouthful of bugs. The nestlings are in a continual carousel of being fed, keeping the parents busy feeding a nest full of an average of 5. But when the nestlings are not getting enough food then they all cluster at the front. So these “jumpers” can actually be accidentally pushed out by the jostling of the babies at the entrance for food.

Martin nestlings that jump due to starvation are usually doomed as the accompanying dehydration is far more deadly than the martin keelhunger. Since all purple martin nestlings water intake comes from the insects that the parents bring, in cases like this the jumpers are all very dehydrated. Not wanting to sound like a pessimist, there is not much that can be done. Feeding a dehydrated and malnourished nestling can cause it to just die faster. Looking at the jumper you can often see clues as to how well fed they are or are not. A pronounced keel (breast bone) shows lack of muscle development from chronic malnourishment. Dry, flaky skin is a sign of dehydration. A  wildlife rehabilitator would also look for signs such as skin turgor or “tenting” of the skin as a sign. Emergency injections under the skin would then be given BEFORE any feedings would be attempted. Water or other liquids can aspirate and kill birds quickly if given by mouth. This article on Hydration of Purple Martins can answer some questions and prevent more harm from being done while a rehabilitator is contacted. If their are other nestlings in the nest sometimes the weaker nestlings “jumping” can increase the survival rate of the nestlings left in the nest. If the jumpers can be hydrated then fed by a rehabilitator, they can often be reintroduced into the nest when the are approaching 21 days old before they fledge. Nest checks become increasingly important to know the age of the nestlings. As lowering housing may sometimes cause fledglings to prematurely fledge out of fright.

Though we provide housing for these wonderful birds, one can’t feel responsible for acts of nature such as drought. We help as best we can and give them a chance to survive. Next year they will return and hopefully with better weather conditions. We learn from our experiences and the next season will bring another chance at life.

Look out for our next entry on some of the other causes of “jumpers”.

(c) 2011 PurpleMartins-R-Us.com

Wooden Purple Martin Houses

Thursday, June 2nd, 2011

Today I received a question and I thought I would share it with you. This DOES NOT pertain to T-14 or Cedar Suites wood houses which use winch / pulley systems and high grade poles designed for the weight of these houses that weigh from 65 to over 100 pounds.

Question

I have a purple martin wooden house that weighs 35lbs. I need to purchase the pole and the plate to set it up. Please recommend the best pole and plate to use to set it up.

ANSWER

It depends on what type of wooden house it is. Is it home made or store
bought? DIY Purple Martin houses that are just flat wood on the bottom, folks mount it to a 4×4 wooden post bought at a lumber yard or home improvement yard. The weight of the house will make it too heavy for a telescopic pole.

Though some websites may say that a telescopic pole can handle up to 25 lbs and sell brackets, galvanized pole or pipe FLANGES can be found in any hardware store. It would be cheaper for you to buy at Lowes, Home Depot or any local hardware store. We do not sell them due to safety concerns. We believe that the weight of the house combined with the height at which martin houses are mounted, substantially increases the risk of pole failure. Though we sell aluminum houses that use galvanized pipe, these
houses have been tested and are proven to support the weight they are designed for.

If you mount to a wooden 4×4 wood post then the base of the house can be screwed onto a post using “L” brackets, also found at any hardware store for under a few dollars.

Unfortunately many wooden purple martin houses sold on the web are poor choices to actually house martins. They are not built with martins in mind. Which is why we do not sell them.


One good tip when buying ANY purple martin house is beware of the term “Easy end of season cleanout” or” top level detaches from the bottom”doing nest checks you want to be able to selectively open compartments. Opening a whole floor at a time is just ASKING for trouble. I mean, where are you supposed to put that portion of the house while you check the other section? On the ground? What about if a nest is close to fledging? The nestlings would be jumping all over the place. Never mind the issues with the posts that these houses are designed to be mounted on. Decorative at best, way to short or impossible to reach at worst.  And I haven’t even mentioned the fact that there are no starling resistant options and the compartments are WAY too small.

Any good purple martin house will have large 6×12 (or even 6×11) compartments and the ability to selectively open portions of the house with minimal disruption. Easy to lower and SREH options show that your and your martins comes first.