Posts Tagged ‘rehabilitation’

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

Update On Late Nest Martins at Rehabber

Wednesday, July 22nd, 2009

I believe the critical period is over and the 2 purple martins from the last late nest will survive. As of yesterday, Busch Wildlife Sanctuary reports that they are eating and gaining weight. It appears as though my efforts to keep them hydrated has paid off. My hopes that they get released back with the colony are dashed however as the day that I removed the most critically thin and dehydrated nestling was the last day that the martins were here in any significant numbers.

It is quite apparent that they were all returning because of the nestlings in the one nest, almost as if to keep them company. Though the parents of the other successful nests did not contribute with feeding the nestlings, they did return as if tied to the colony site while it was still active. Once the nests were empty, they were obviously released from whatever ties they had to the location and have most definitely moved on. Yesterday I counted 6 martins on the wires for less than 5 minutes. They did not land on the housing at all which leads me to believe that they were not my birds, only passers-by. Today there were none. And so the days have passed since the nestlings were taken to the rehabilitation facility.

Unfortunately this does not bode well for the nestlings/fledglings, as far as their survivability post rehabilitation. Without parents to instruct them on feeding, their chances are poor. But there may be a new hope for some rehabbed nestling martins that miss the opportunity for the post fledging instruction period that they usually receive from their parents. In a post on the PMCA forum, a purple martin conservationist in California has had positive, albeit early results from a radically new and controversial theory in the rehabilitation of nestling purple martins. Check out the thread HERE.

In short, it describes how in past years in banding and releasing into colonies, nestlings that required rehabilitation, that none had been recovered. But last year, 3 nestlings that were rehabbed were “taught” to catch flying insects in a large flight cage. These 3 purple martins were them banded and released. This year one of the 3 birds was sighted in the area having obviously survived and returned from migration. This just may be a huge turn in the current thinking in rehabilitating purple martins. If this hypothesis is correct purple martins may very well have new hope when it comes to purple martins that miss that critical post fledging instructions. Rehabilitation that may have been in years past-delaying of the inevitable, may very well be  a new beginning for these birds.

Many thanks to Daniel Airola, from Sacremento, California for this important information.