This paper: http://polaris.nipr.ac.jp/~penguin/oogataHP/pdfarticles/23p227-233.pdf published a decade ago outlines how these geolocators work. And they are really a very elegant little gadget. But the accuracy is not nearly close enough to say that a Bermuda Petrel was within the 3 nm state waters based on that point. Accuracy of these devices can be off by several miles – that is OK. They are intended for large-area mapping, like what part of the ocean does the Bermuda Petrel use in winter, not necessarily that it strayed into coastal Maine waters.
I would say based on these data that yes Bermuda Petrels clearly enter the Gulf of Maine and come up onto the continental shelf. It would be interesting to see the unique IDs of the locators to determine if that is one wandering bird or whether it was multiple birds. But I wouldn't make a case for putting it on the state list – yet. Hypothetical certainly.
===============================
Michael Smith MS GISP
State GIS Manager, Maine Office of GIS
State of Maine, Office of Information Technology
michael.smith _at_ maine.gov 207-215-5530
Board Member, Maine GeoLibrary
Education Chair, Maine GIS Users Group
State Rep, National States Geographic Information Council
State House Station 145
51 Commerce Drive
Augusta, ME 04333-0145
69o 47' 58.9"W 44o 21' 54.8"N
From: maine-birds@googlegroups.com [mailto:maine-birds@googlegroups.com] On Behalf Of Jeff Wells
Sent: Friday, December 12, 2014 10:48 AM
To: Maine Birds
Subject: [Maine-birds] Could Bermuda Petrel have occurred in Maine waters?
I came across several intriguing maps of tracking data from two seabird species based on geolocators that would be fairly astounding if the locations are accurate or even close to accurate.
The most surprising would be this map of one of the world's rarest birds, the Bermuda Petrel, which has a point plotted on the map that would have placed the bird between Monhegan Island and the mainland on April 9, 2010 (if I am reading the date correctly). That map can be seen at this link: http://seabirdtracking.org/mapper/?dataset_id=741
The other map is of Audubon's Shearwater locations from birds that had the geolocators affixed in the Bahamas. The map is not interactive so can't be zoomed in to see exactly where the locations have been plotted but it shows many locations plotted in the Gulf of Maine and generally in the waters off the Northeast U.S. and the Maritimes where there are very few records of Audubon's Shearwater. The Audubon's Shearwater tracking map can see at this link: http://www.atlanticseabirds.org/aush-bahamas
There are issues with analyzing geolocator data that must be carefully considered when deciding the accuracy of points, etc., and I will leave it to others to comment about that but if any of these plotted locations are even in the ballpark, then it would suggest that Audubon's Shearwaters may be regularly undetected or misidentified as Manx Shearwaters in our waters. I'm not sure what to think about the Bermuda Petrel locations. Maybe the Maine Birds Records Committee should take on the task of investigating this information to see if it is credible?
If anyone wants to talk more about these fascinating maps and implications in person, Allison and I will be at LL Bean's on Saturday from 11-1 for a book signing and conversation.
Jeff
Jeff Wells
--
Maine birds mailing list
maine-birds@googlegroups.com
http://groups.google.com/group/maine-birds
https://sites.google.com/site/birding207
---
You received this message because you are subscribed to the Google Groups "Maine birds" group.
To unsubscribe from this group and stop receiving emails from it, send an email to maine-birds+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
0 comments:
Post a Comment