As part of this summer’s Gull Population Biology internship, I am looking at the wealth of information available in the Gulls of Appledore database and trying to figure out what can be displayed and analyzed spatially, using QGIS. My first question was of natal philopatry: are our gulls particular to exact spots? The parameters I chose were fairly pinpoint, and although I didn’t see much of this “extreme” natal philopatry (within 50 meters), I did encounter some interesting instances of natal philopatry – however anecdotal they may be. I thought, who better to share these noteworthy examples with than the readers of a blog dedicated solely to the gulls of this beloved northwest Atlantic rock?
First comes the life history of two Herring Gulls, K39 and K40. K39 and K40 were banded as chicks in 2010. Their natal nest site (although no nest was tagged or attributed to them at the time of banding) is described as “Transect 15 at border of Transect 14.” As far as I can tell, there are no other chicks from that year with this same nest site description. I cannot say with any degree of absolute certainty that these two birds are related, but it is an interesting question to ponder – particularly when you take into account what these two gulls have done upon their return to Appledore Island.
Liam Berigan is the Field Ornithology Intern this summer and as such, he is responsible for the monitoring of several sub-colonies of Herring Gulls, including those at the border of FMS Transect 14 and 15. One of his monitored nests happens to belong to K39. While assisting Liam on his monitoring, I had made note of that fact, and resighted K39 on the nest in our database. It was shortly thereafter when I noticed a banded gull, K40, who was nesting perhaps a half meter from K39. When I entered these two birds, it didn’t immediately occur to me that they might have a shared history, but as I started searching through records of gulls banded as chicks and returned as adults to nest, I realized these two had the same unique natal nest site description. I looked back at the previous year’s nest summary for both birds, and discovered they had been nesting next to one another in 2015 as well.
The interesting bit doesn’t stop with the realization that these two are, at the very least, dedicated neighbors. It was just a short time ago that we discovered K39’s chicks (banded with colored poultry bands so Liam can mantain hatch order and thus derive differential survival between chicks) on K40’s nest, with K40’s chick! Quite the pile. K40 was closeby, loudly expressing their concern about our proximity to this confusing cluster of fluff.
Needless to say, we are eager to band these chicks and see what happens in the coming years!