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Wednesday, January 21, 2015

Tejon Ranch Conservancy 7th Annual Christmas Bird Count, By Dr. Phoebe Prather; Senior Biologist

Tejon Ranch Conservancy staff and 26 guests spread out across Tejon Ranch on Monday, December 15th for our annual 7th Annual Christmas Bird Count.  We were able to field five teams to bird the San Joaquin Valley and Antelope Valley sides of the Ranch.  Teams counted a combined total of 103 species.  It was a quiet year, in terms of number of birds tallied, we were well below the number of species counted last year and we were not able to add any new species to the Tejon Ranch Bird List, but it was still a wonderful day filled with birds, the beauty of the landscape and quiet companionship.  One couldn’t ask for more in a day spent in the great outdoors. 

Storm systems had come through the area the week before the count, pouring rain on the lower elevations and depositing snow on the mountaintops, with another system predicted to move into the area the day of the count.  It was with trepidation that people gathered at their respective meeting places, unsure of road conditions and what the day may bring.  These dedicated supporters of our organization had woken in the dark hours of the night to drive to Tejon from their far off homes in Ridgecrest, the greater Los Angeles area, Ojai, Santa Barbara, San Luis Obispo, and the Kern River Valley to help us conduct our CBC.  Acquaintances that have bonded through our birding events greeted each other fondly as the sky began to lighten, telling tales of their adventures since the last time they had met and the birds they had already tallied since arriving at the gate.  Soon teams headed off in opposite directions to see what they could see (Photos 1, 2, 3).  I led a team on the San Joaquin Valley side of the Ranch.  Away from the canyons, where the wind whipped over the crest of the Tehachapis, the day was calm and the sky provided a revolving show of cloud formations throughout the day.  The recent precipitation had spurred on germination and the landscape was coated in a carpet of green that had not been seen in over a year.  Across the hillsides the skeletons of the bare California Buckeye (Aesculus californica) trees showed silver in contrast to the dark green of the live oaks (Quercus wislizenii and Q. chrysolepis) (Photos 4 and 5).  Worries about road conditions and storms disappeared as the sky continued to brighten and the birds began to sing.

Results from all CBCs are posted on our website.

Photo 1.  Great-horned owl (Bubo virginianus) hunkered down in a tree cavity in a cottonwood (Populus fremontii) in El Paso Canyon.  Photo by Devon Pryor.

Photo 2.  California condor (Gymnogyps californianus) perched on a tree on Winters Ridge.  Photo by Devon Pryor.

Photo 3.  Volunteer birder scanning the ridges.  Photo by Devon Pryor.

Photo 4.  A hillside in Tejon Canyon scattered with the silver skeletons of leafless California Buckeyes (Aesculus californica).  Photo by Phoebe Prather.

Photo 5.  A flock of wild turkeys (Meleagris gallopavo) in Tejon Canyon.  A large flock of 60-70 is seen in Tejon Canyon every year during the Christmas Bird Count.  Photo by Phoebe Prather.

The Beginning
The Christmas Bird Count (CBC) is a long-standing program of the National Audubon Society.  It is the longest running Citizen Science survey in the world with over 100 years of citizen involvement.  Prior to the creation of the CBC, there was a holiday tradition known as the Christmas “Side Hunt.” (1)  Gatherings of people divided into teams and went out and shot as many birds as they could.  The team that returned with the largest number of dead birds was the winner of the event.  Frank Chapman, a famed ornithologist at the American Museum of Natural History, the editor of Bird-Lore and an early officer in the budding Audubon Society, recognized that bird populations could not withstand this over-hunting.  He proposed that people should count birds on Christmas Day instead of shooting them, leading him to the idea of a “Christmas Bird Census.”  The first Christmas Bird Census, later renamed the Christmas Bird Count, was held on December 25, 1900.  Twenty-seven volunteer birders participated in 25 count locations that spanned from Toronto, Ontario to Pacific Grove, California with most counts occurring near population centers in northeastern North America.  The 25 counts totaled a combined 89 species.

Amazing stories of dedicated citizen scientists have come from the CBC experience since the creation of the count. 
  • Only one of the inaugural CBCs occurred in the southern United States.  A single volunteer, Mrs. L. G. Baldwin, considered the founding mother of the CBC, counted 8 species in Baldwin, Louisiana: killdeer, blue jay, Carolina chickadee, Carolina wren, red-winged blackbird, grackle species, northern mocking bird, and turkey vulture (2).  She conducted her count again in 1901 and added four more species, the red-headed woodpecker, crow species, tufted titmouse, and ruby-crowned kinglet.  In 1903, Mrs. Baldwin continued her citizen science activities when she had an article published in American Ornithology about her concern over the Cardinal Grosbeak, later renamed the Northern Cardinal, and its decline due to hunting and trapping: “The brilliant plumage of the cardinals makes its end a tragedy. In Louisiana they are hunted and trapped for sale, as cage birds, until they are nearly exterminated. Their pathetic fate appeals to bird lovers, and unless something can be done for their protection the Cardinal Grosbeak will be gone from the wild bird life of this state."  With the shifting of philosophies on wildlife brought on by the creation of programs such as the CBC and the building of a citizen scientist base, it is species such as the Northern Cardinal that are now once again considered to be common birds.
  • In 1916, two young girls, with the help of their aunt, participated in a CBC in Georgia (3).  Their story, published in the magazine Bird-Lore, illustrates the importance of raising children in nature and exposing them to citizen science projects early in their lives: "We are two little girl-sisters who are living in Georgia now with our papa and mama. We were born in Knoxville, Tenn., on Chestnut Hill, where there are a great many birds, and Aunt M who loves birds, taught us their names. When I was two and a half years old I could name twelve birds. Aunt M came from Tennessee to spend Christmas with us. This morning we took little sister B and walked through Inman Park where there are a great many evergreen trees called water oaks. We were looking for birds for our Christmas Census. We saw: 12 Blue Jays, 6 Towhees, 5 Cardinals, 2 Mockingbirds, 25 in all. We heard a Flicker and a Carolina Wren and thought we heard a Bewick’s Wren. The weather is so warm that we have the windows open."
  • Many other stories are reported each year, ranging from tales of counting ravens at Prudhoe Bay, Alaska, birding in Belize, and the CBCs along the Gulf Coast after the BP oil disaster.  These stories and others are posted on the National Audubon Society’s website for all those interested in the wide-range of CBCs occurring each year.

Survey Methods and Count Circles
Each Christmas Bird Count occurs within a designated 15-mile (25-km) diameter circle (4).  Volunteers follow specified routes through the circle and count every bird they see or hear.  The individual CBCs are conducted between December 14 to January 5 of that count year and each count is conducted in one calendar day.  Thousands of volunteers participate across the United States, Canada and many countries in the Western Hemisphere.  Participation has continued to increase every year since 1900.  By 2008 there were 2,113 CBCs and 59,918 volunteers (Figures 1 and 2) (5).

Figure 1. Locations of Christmas Bird Count circles in the Western Hemisphere (8).

Figure 2. Number of Christmas Bird Counts and participants over the years (5).

Data and Analysis
Over a century of data has been collected as a result of the CBC.  This data allows researchers, conservation biologists, and other interested individuals to study the long-term health and status of bird populations across North America.  The data has been used to build strategies to protect birds and their habitat.  It shows local trends in bird populations that can indicate habitat fragmentation or an immediate threat.  An example is the American black duck.  In the 1980’s, CBC data documented the decline in the wintering population of the species (8).  Conservation measures were put into place to reduce hunting pressure and the species has rebounded.

In 2007, CBC data was instrumental in the development of two Audubon Society State of the Birds Reports (6).  Common Birds in Decline analyzed 40 years of CBC data and revealed an alarming decline in some of America’s most beloved and familiar bird species.  There are 20 bird species on the list, all of which have lost at least half of their populations since 1965.  The average population of these common species has fallen by 68 percent, with some species having declined by 80 percent.  WatchList 2007 identified 176 species in the continental United States and 38 species in Hawaii that need immediate conservation action.  The report lays the groundwork for a standard to guide conservation priorities among conservation organizations and government agencies.  It helps focus attention on “red” species, species of greatest concern, while highlighting other sensitive “yellow” species so action can be taken to keep them off of the “red” list. 

In 2009, CBC data was essential in two more reports (8).  The Audubon’s Birds and Climate Change  analysis documented how climate change could affect the ranges of 588 bird species.  Three decades of citizen science observations were used to define the range of temperatures, precipitation, and seasonal changes each species needs to survive.  Climatic models based off these data indicate that 314 species will lose more than 50 percent of their current range by 2080.  126 of these species were classified as climate endangered and are projected to lose more than 50 percent of their current range by 2050.   A collaborative report by the North American Bird Conservation Initiative, 2009 State of the Birds Report, also used CBC data.  This was the first ever comprehensive report on bird populations in the United States.  It showed that nearly a third of the 800 bird species in the United States are endangered, threatened or in significant decline due to habitat loss, invasive species, and other threats.   But the report also highlights examples where habitat restoration and other conservation measures have reversed previous declines.   

The U.S. Environmental Protection Agency included Audubon’s climate change work described above as one of the agency’s 26 indicators of climate change in their 2012 report.  The report shows that among 305 widespread North American bird species, the average mid-December to early-January center of abundance has moved northward by more than 40 miles between 1966 and 2013 (Figure 3).  Of these species, 48 have moved northward by more than 200 miles.  These northward moving trends can be closely related to increasing winter temperatures.  Analysis of the CBC data has also indicated that bird species have moved their wintering grounds further inland from the coast since the 1960s.  Inland areas tend to experience more extreme cold than coastal areas, but these extremes are becoming less severe as the climate changes, allowing inland areas to become suitable habitat. 

Figure 3.  The annual change in northward movement of bird species centers of abundance for 305 widespread bird species in North America from 1966 to 2013.  The shaded band shows the range of values, based on the number of measurements collected and the precision of the methods used (6,7).

The online CBC database can be a useful tool to guide further, more in-depth research on bird distributions across North America and is available to the public.  Case study reports of specific species such as the American black duck, hooded merganser, and evening grosbeak, as well as communities of birds such as waterbirds and land birds of the boreal forest have been analyzed using CBC data.  Over 200 peer-reviewed articles have resulted from an analysis of CBC data.  It is an incredible source.

In the beginning, it was hunting that ignited bird conservation efforts.  Today, the challenges we face are much more difficult to address than just changing hunting regulations.  Continuing to track populations as habitat disappears and the climate changes will be essential for the conservation of our bird species and natural communities.  There is more work to be done than organizations and agencies can do by themselves.  It is essential to continue to build a strong citizen scientist base and to promote projects in which they can help and take ownership in our natural resources.  With a staff of 7, many of the efforts of the Tejon Ranch Conservancy are reliant on volunteer citizen scientists. 

Tejon CBC
The Tejon Ranch Conservancy has been conducting a Christmas Bird Count on Tejon Ranch since 2008.  The 15-mile diameter circle fit perfectly into the body of the Ranch (Figure 4).  The circle is divided into 5 areas.  We typically are only able to cover the low elevation portions of the Ranch and using four or five teams we are able to cover portions of areas 1, 2, 3, and 4.  We usually have a turnout of 20-25 volunteers to help us.  We have designated locations within each area that teams visit which allows us to collect consistent data in specific places every year.  We now have a data set encompassing seven years.  With this data we are able to track our wintering bird populations over time.  We have seen that we get an influx of raptors occupying the Ranch during the winter.  Several bald eagles spend time here and are then gone by spring.  Our red-tailed hawk and golden eagle numbers also increase during the winter.  Reservoir Number 2 on the San Joaquin side of the Ranch fills with waterfowl species such as ruddy ducks, eared grebes, American wigeon, ring-necked ducks, American coots and canvasbacks.  Combined with our spring Breeding Bird Blitz, which uses the same methodology as the CBC, we will be able to piece together long-term trends of the resident, wintering, and breeding bird species that occur on the Ranch.  Stay tuned for results from that future venture into data analysis!

Figure 4. Tejon Ranch Christmas Bird Count circle.

(1)   National Audubon Society.
(2)   National Audubon Society.
(3)   National Audubon Society.
(4)   National Audubon Society.
(7)   National Audubon Society.