Great Blue Heron Monitoring Program
Marian Bailey is lead biologist for the Nisqually National Wildlife Refuge (NWR) Great Blue Heron monitoring program. A heron colony along the west side of McAllister Creek in the NWR has been the focus of this monitoring effort. Ms. Bailey provides the following responses to an interview with Seattle Audubon volunteer, Fred Bergdolt, regarding this ongoing study.
- What are the goals and objectives of the NWR Great Blue Heron monitoring study?
a) To determine the reproductive success of the Great Blue Heron colony each nesting season using non-invasive and non-disruptive monitoring methods.
b) To record Great Blue Heron activity at the nest colony.
c) To determine the trend of reproductive success over time.
d) To determine if external factors are affecting Great Blue Heron nesting success.
e) To contribute data and share information regarding Great Blue Heron reproductive success or failure with the Washington State Department of Fish and Wildlife.
- Can you describe your monitoring methods?
Near the courtship and breeding time of year, knowledgeable volunteers record data when birds are observed congregating at the nest colony. One volunteer (the primary observer in past years) locates a position where they have an open view of the colony from approximately 100-150 yards away. They remain quiet while using a spotting scope to carefully watch and record activity and behavior data for members of the Great Blue Heron colony. The volunteer generally watches colony members for approximately 3 hours at a time and up to 3-4 times weekly. They watch for adult courtship behavior, brooding activity, chick/young bird development and potentially, for fledging activity. In addition, they watch for and record any interactions with other wildlife or human beings (disturbance).
- When does monitoring take place? Is this an ongoing monitoring effort?
When courtship behavior is first observed each spring, one of the NWR Volunteer Rovers will inform the Refuge biologist. Then, monitoring begins in earnest. The same 2 or 3 volunteers have been conducting the monitoring work on the colony activity for many years now. They know the methods, and they know how to be relatively unobtrusive and non-threatening while collecting observation data. These volunteers do not usually require much guidance from Refuge staff.
- Are you interested in additional volunteers?
As I mentioned above, volunteers are the primary observation specialists for this program. For the most part, we have dedicated volunteers that handle tasks associated with monitoring Great Blue Heron nesting activity. Currently, more volunteers are not needed for the Great Blue Heron monitoring effort.
- Can you share some of your preliminary findings?
Approximately 20 years ago, the Great Blue Heron colony along McAllister Creek was quite small with perhaps 5 nests. Over time and for an extended number of years, the colony grew as large as 50-70 nests. Since that peak, the number of nests and mated pairs has been steadily declining. In the recent past, the colony was limited to just 4-6 nests. Virtually no young birds fledged.
In Spring 2003, approximately 12 Great Blue Herons stood within or near the colony site. A few birds stood on top of old nests, but did not appear to bring twigs or other material to re-furbish the nests. These birds never attempted to lay eggs. Within a month or so, they abandoned the nest colony. Great Blue Herons were observed foraging in the Refuge estuary on a continuing basis throughout the year.