Water Supply Protection Gull Study

A variety of birds utilize the Wachusett and Quabbin Reservoirs for breeding, migratory stops, roosting, and feeding. Most species, like the common loon, occur in such low numbers that they pose little threat to water quality. However, some species – such as gulls, ducks and geese – can concentrate in large numbers for an extended period of time. DCR operates a highly effective gull harassment program at both reservoirs to limit the pollutants from these birds; Quabbin and Wachusett Reservoirs continually meet all state and federal drinking water standards.

Three species of gulls roost nightly on Wachusett and Quabbin Reservoirs: ring-billed, herring, and great black-backed gulls. Their numbers tend to increase during the winter. Unfortunately, there is little scientific knowledge on these wintering gulls. Therefore, as part of the gull control program, DCR is conducting research related to the movements and behaviors of ring-billed, herring, and great black-backed gulls.

This research program is designed to address the following questions:
    1. What and where are the seasonal food resources for each gull
        species?
    2. What are the movement patterns between feeding, loafing and
        roosting sites?
        Do they move between the DCR water supply reservoirs and
        “alternate roosts”?
    3. What are the population dynamics of gulls in Massachusetts?
        a. Where do they nest?
        b. What are the sources of mortality?
        c. What is their lifespan?

Banding and Tagging
Initial trapping was conducted throughout January, February, and March 2008, utilizing three methods: a walk-in nest trap, Steele’s net, and rocket net. All methods successfully captured the targeted species, although the rocket net and Steele’s net were much more effective and efficient. Starting in the fall of 2008, a net launcher and net gun were exclusively utilized for trapping.

Following capture, all birds are fitted with an aluminum federal leg band. A uniquely numbered colored leg band is placed on the opposite leg of all birds [Picture 1]. Finally, on most birds, a colored, uniquely numbered wing-tag is attached to each wing. These wing-tags make long-distance identification possible, particularly when it is difficult to see or read the leg bands [Pictures 2-4]. Wing-tags are color-coded based on the capture site’s proximity to either Wachusett or Quabbin Reservoir [Picture 5].

Tracking Gulls Via Satellite

A small number of gulls are fitted with satellite transmitters instead of wing-tags.  Several types of transmitters have been deployed: a 45-gram GPS equipped transmitter on the adult great black-back gull; 30-gram and 22-gram GPS equipped transmitters on adult herring gulls; a 20-gram non-GPS equipped satellite transmitters on herring gulls; and a 9.5-gram non-GPS equipped satellite transmitter for the ring-billed gulls.  All transmitters are solar-powered and have the potential to last several years.  There are currently satellite transmitters on 5 ring-billed gulls, 9 herring gulls, and 1 black-back gull.

Click on the following links to follow the flight pattern of two of these gulls.  You need to have Google Earth on your computer to view this data.  Each point represents one specific data point transmitted from the backpack unit to a satellite.

ID #87428: Adult ring-billed gull.  Captured 11/10/08 at Searstown Mall, Leominster, MA.  Locations are obtained by a simple transmission from the bird to the satellite without GPS technology; as a result, these points are a bit less accurate than #87433.

ID #87433: Adult herring gull.  Captured 11/5/08 at the Blackstone Valley Water Abatement facility, Worcester, MA.  Locations are obtained with GPS technology, so these points are extremely accurate.

How the Public Can Help
DCR is asking the public for help with this study. Almost 250 gulls have been captured and tagged near the Wachusett and Quabbin Reservoirs. DCR plans to continue trapping, banding, and wing-tagging through the spring of 2009. Wing-tags can be seen from a distance, and the numbers on the tags are easily read with binoculars or sometimes even with the naked eye. All sightings are very important to this study. Sightings have already been received from residents, birders, and the federal bird banding lab, ranging from central Massachusetts to Maine, as well as Manitoba, Newfoundland and Labrador, Canada.

Contact Information
Please contact Ken MacKenzie at Ken.Mackenzie@state.ma.us (508-792-7423 x313) or Dan Clark at Dan.Clark@state.ma.us (508-792-7423 x215) with wing-tag information.

1. Federal Aluminum Leg Band and Number Colored Leg Band

2-4. Unique number Wing-tags

5. Quabbin and Wachusett Reservoir Wing-tag Codes

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