Lake Havasu City is bird-rich. But beyond the city limits in riparian areas, the birds are even more plentiful. That’s one reason two nearby sites have been surveyed for the National Audubon Society’s Christmas Bird Count for several years.
Now in its 120th year, the nationwide CBC consists of a tally of all birds detected within a designated 15-mile diameter circle on a single day within a few weeks around Christmas.
Locally, those counts took place on Dec. 29 at the Bill Williams Wildlife Refuge and then again on Dec. 30 at the Havasu Wildlife Refuge. Friends of the Refuges, a volunteer organization, conducted the counts, said Jude Gilford, the group’s vice-president. Another member of the club, Marge Penton, served as the data compiler.
Gilford said there were some surprises.
“There were two kinds of birds that were unusual in the Bill Williams CBC. They have been seen in the area in past years, but they are rare,” she said. “That would be three surf scoters and one Eurasian wigeon.”
According to the Audubon Society’s web site, the scoter is a large sea duck that is found on both coasts. Eurasian wigeons are also ducks that are seen annually in North America and likely come from eastern Siberia and Iceland.
For the Bill Williams CBC, Penton said the preliminary count was more than 5,400 birds counted from 104 species. For that effort, 26 people participated on teams covering 10 routes. It was the 20th year for the CBC.
For the Havasu CBC, 25 people participated; teams covered eight routes. It was the 10th year for that refuge’s count.
“The preliminary data for this CBC resulted in over 7,500 birds counted from 110 species,” she said.
How it’s done
On the day of the count, volunteers split up into two or three-person teams and followed specific routes, Gilford said. They hike, drive or kayak to specific areas in the refuges. There’s an expert birder on each team as well as photo/audio equipment to record bird songs for positive identification.
The teams start at 8 a.m. and end mid-to late afternoon. It’s challenging work because, well, birds fly off. Notoriously skittish, they move quickly.
Big flocks can’t be counted precisely. Also, knowing if a bird has been counted twice can be difficult. Owls aren’t counted because that is nocturnal work.
The southern refuge site is centered at the Bill Williams River Delta, Gilford said. The Havasu CBC takes place in and around the north end of the Havasu National Wildlife Refuge. The center of the circle is in Topock Marsh and goes north to Courtwright Road, west into Needles, east to Golden Shores, and seven miles south of I-40, Penton said.
Penton soon will submit the data and supporting documentation to a regional Audubon official in Prescott who will verify and finalize the results.
Why it’s important
By tracking trends of bird numbers over time, the National Audubon Society contends that the CBC enables monitoring of winter bird populations and the overall health of the environment. Although the avian count program was neither intended nor designed for exact population monitoring, the long-running wildlife census assesses the health of bird populations and can help guide conservation action.
The annual CBC final counts note changes in distribution and abundance.
Critics of the CBC say the effort is weakly standardized. Variables include amount of effort, weather, time of day, skill of observers, mode of travel (driving versus walking), habitat and distribution of effort among habitats.
Still, Gilford and Penton believe the CBC yields valuable information.
“We make sure our counts are as accurate as possible,” Penton said. “Even within the teams, there is sometimes a debate over bird identifications. That’s why it’s important to talk it over. We want to get it right.”
Learn more about the Friends of the Refuges at the group’s open house on Thursday at the Aquatic Center, 5:30-6:30 p.m. At that time, guests can also meet refuge staff members.