Trends identified in Tri-City Christmas bird count
A species of bird that was virtually non-existent in the Tri-Cities only a few years ago has seen a significant increase in its local population, according to statistics from the recent Christmas bird count.
Elaine Golds, a member of the Burke Mountain Naturalists and a volunteer with the annual count, told The Tri-City News the population of the Anna's hummingbird has exploded in the area.
Prior to 2008, the species had not turned up in the Christmas count statistics. This year, more than 25 were counted, an increase from five last year and nine in 2011.
"Their [overall] numbers seem to always be increasing," Golds said. "There are so many people that have feeders for them."
John Reynolds, another member of the Burke Mountain Naturalists and an ecologist and professor at Simon Fraser University, said the Anna's hummingbird population has been slowly expanding northward for the last several years. He said they have become increasingly common in the Lower Mainland and in the southern region of Vancouver Island.
"It's thought that a combination of milder winters and an increase in hummingbird feeders may have helped increase their numbers," Reynolds said. "It's amazing that a nectar-feeding species can survive our winters."
Overall, Christmas bird count statistics stayed relatively consistent this year. More than 8,500 birds were counted, comprising about 83 species, according to the data, which was collected by 60 volunteers across the Tri-Cities on Dec. 14.
That number is up from 2012, when 7,100 birds were tallied, but down from 2011's record, which saw 10,000 birds counted.
Numbers can be affected by a variety of factors, weather among them, and year-to-year fluctuations are common, Reynolds said.
A one-year snap shot may not mean much but decades of data collection help researchers understand long-term trends in the local bird population, he added. For example, Reynolds' analysis has found the neighbouring Pitt Meadows area has seen a decrease in the types of birds that rely on what is called rough pasture — land similar to that found at Colony Farm in Coquitlam. He attributes this decline to the fact that many farmers on the east side of the Pitt River have switched from using their land for cattle grazing to berry growing.
"We can actually document how changes in land use practices affects bird populations," he said. "Intensification of agriculture has directly correlated in an 80 to 90% decline in some of these species that require open fields."
The Burke Mountain Naturalists organize the annual bird count west of the Pitt River. All of the data is collected and sent to Bird Studies Canada, which shares the the statistics with the National Audubon Society in the U.S.
The Christmas bird count started in the early 1900s as a way of replacing the annual bird hunt. In the Tri-Cities, numbers have been kept since the early 1990s.
BIRD COUNT STATISTICS FOR THE TRI-CITIES
Year Species Total
2013 83 8,500
2012 80 7,100
2011 78 10,000
2010 81 8,700
2009 72 6,500
2008 81 6,150