Supporting scientific studies, educational opportunities, and protecting the unique Great Marsh in Northern Chester County

Supporting scientific studies, educational opportunities, and protecting the unique Great Marsh in Northern Chester County

Category: Projects


Motus Project Update

You may recall that I reported last year on a bird banding project that GMI is supporting. To recap, MOTUS is a program for deploying automated receivers across the country to pick up coded signals from bird tags. 

We are providing technical support to the Northeast Motus Collaboration (#48) and your scribe is acting as a volunteer technical advisor to this group.  There has been extensive bird tag testing at Marshlands with field tests and also drone missions. 

A technical report has been published where we compare two Motus-compatible tags: The NanoTag and the LifeTag/PowerTag. The “NanoTag” is manufactured by Lotek and has been widely used by researchers using the MOTUS system since the beginning. The LifeTag technology was developed by Cornell University, and has since been licensed to Cellular Tracking Technologies (CTT) from which they have developed the CTT LifeTag and CTT PowerTag. These tags demonstrate greatly improved performance in both detection distance and code identification.  The LifeTag is solar powered and will run forever as long as the sun shines whereas the PowerTag is powered by a tiny battery which works for birds that prefer to travel at night.

We have tested a number of samples of each tag variant and the LifeTag and PowerTag far out perform the NanoTag in detection distance.  The NanoTag is detectable only to about 0.5 km whereas the CTT tags have been detected out to 8 km on tests at Marshlands.  Some recent tag detections have been as far as 40 km over water.  This difference in performance is probably due the higher operating frequency (434 MHz) of the CTT tags compared to the NanoTag (166 MHz) which makes the tag antenna more efficient. The improved coding system provides a better signal to noise ratio which also increases detection range.

For those of you who are interested in the technical details here is a link to the test report.  We are also home to one of over 375 automated receiver systems across the globe.


The Marshlands Catwalk Repair Project

A group of five intrepid catwalk repair specialists set out on a chilly sunny morning to replace the rotted planks of the 500 foot long span that traverses the lower end of the Great Marsh. No easy undertaking by anyone’s standards. Jeff, the most experienced among us, had theoretically devised an ingenious way to detect the defective planks…by stepping on them. As evidenced by the broad smile on Jeff’s face the undeniable proof of his theory was apparent.

John, the fastidious keeper of tools for the day’s project, decided that after a hard morning’s work, it was time to clean and pack up the tools for the return trip. To that end he tossed the muddy and soiled crowbar into the clear water below. And in the selfless team spirit that John exudes, he then jumped into the icy water to retrieve the freshly washed tool.

Thanks to the mentoring and examples of both Jeff and John, both an inspiration to the other team members, the project was a resounding success. Jeff, Jordan and Joe gained some valuable experience for the next project. Our new team slogan… Watch and learn!”

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Jeff after testing an old section with a face plant!
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MOTUS at the Great Marsh

As some of you may know I have been working on a technical project to support a program of deploying automated receivers across the country to pick up coded signals from bird tags. I felt they could use some technical guidance from a retired electrical engineer and Ham radio hobbyist (W3ASA) since most of the folks involved are biologists and ornithologists. I have been working with Willistown Conservation Trust who are spearheading this effort in Pennsylvania. They recently received a $500K grant from US Fish and Wildlife which will be used to deploy more automated receivers throughout the mid Atlantic region. My role in this will be to advise on appropriate antennas that will be mounted on towers which will provide good directional information, be cost effective, and relatively easy to install in remote locations.

As part of GMI’s science mission we are supporting a test facility that will enable field testing of various antenna combinations and bird tags. The tags currently in use operate at 166 MHz. Cornell has developed a new tag which operates at 432 MHz in addition to allowing smaller antennas they have orders of magnitude more code combinations than the 166 MHz tags currently in use. We have antennas set up for these tags as well and are currently running tests on them.

Since Great Marsh has been designated as an Audubon Important Bird Area(IBA) it is appropriate that GMI support new technologies that will enable ornithologists and biologists to gather new information that was not possible without the support of this technology. See for more information. This link shows receiver locations worldwide and if you zoom in far enough you will see the two Marshlands deployments

Jim Moore, October 4, 2018