Got Acorns?

If you have acorns in your area, be on the look out for band-tailed pigeons this winter. Band-tailed pigeons are California’s only native pigeon and this time of year, they will fly great distances to find acorns. Band-tailed pigeons are one of the rare bird species that will actually swallow acorns whole! Unfortunately, this behavior also makes them more susceptible to Trichomonosis, a disease caused by a single-celled microscopic protozoan parasite, Trichomonas gallinae.

Band-tailed pigeon. Photo by Krysta Rogers.

Adult band-tailed pigeon showing the characteristic white crescent and iridescent greenish-bronze patch of feathers on the hind neck and black band on the tail, for which the species was named. Photo by Krysta Rogers, 2013.

The parasite lives in the mouth and throat of infected birds, causing caseous (“cheese-like”) lesions to develop in the bird’s mouth or esophagus. As the lesions become larger, the pigeons can no longer swallow acorns, leading to weight loss and eventually death. The lesions also may cause the pigeon to suffocate, if they block the airway.

Band-tailed pigeons with Trichomonosis. Photos by Jeff Cann & Krysta Rogers.

Fig. 1: A band-tailed pigeon showing signs of infection with Trichomonosis.
Fig. 2: A dead band-tailed pigeon observed during a Trichomonosis die-off in 2012.
Fig. 3: Caseous lesions in the oral cavity of a band-tailed pigeon with Trichomonosis.
Photos by Jeff Cann (Fig. 1) & Krysta Rogers (Fig. 2 & 3).

While this disease can make pigeons sick any time of the year, large-scale die-offs only occur during the winter, in some years. The last series of mortality events were reported in 2012 in California, when up to 10,000 pigeons were estimated to have died between December and March. Recent research by CDFW suggests that these mortality events are more likely to occur in winters with low precipitation, similar to the conditions we’ve been experiencing so far this winter.

So, if you have acorns, be on the lookout for band-tailed pigeons and enjoy watching them comically hang from the branches as they try to reach an acorn. Hopefully, the pigeons will not experience any die-offs this winter. However, if you do happen to see pigeons that appear sick, such as showing signs of weakness, labored breathing, breathing with their bill open, drooling, reluctance to fly when approached, or are dead, you can help by reporting the mortality to the Wildlife Investigations Lab.

If you have any questions, or would like to report sick or dead band-tailed pigeons, contact Krysta Rogers at 916-358-1662.

Swainson’s Hawk Rescued from Busy Freeway in Davis, CA

I was returning to the Region 2 office from UC Davis Tuesday June 19 when I saw an injured hawk in the shoulder of the fast lane – right on the yellow line of eastbound Interstate 80. Pulling into the shoulder near the center divide, I assessed the situation and made a call to Wildlife Investigation Lab’s (WIL) Stella McMillin, Krysta Rogers, and veterinarian Deana Clifford. Our rescue mission was simple, but dangerous: rescue the hawk from the freeway in a manner that was safe for the hawk, me and freeway traffic.

Adult Swainson’s Hawk

The hawk was alive but injured, and I sensed that if I approached it, it might go directly into traffic.  If I were to do nothing, the hawk still could head into traffic and cars were starting to swerve to avoid the hawk. Stella and Krysta called the California Highway Patrol while Deana contacted Yolo County Animal Services for further assistance. She also alerted the UC Davis Veterinary Medical Teaching Hospital (VMTH).

CHP Officer Marco Rivera was on the scene and ready to help within minutes. While going over a rescue plan, the hawk managed to move into the center divide among the oleander bushes – safely away from traffic. Knowing this was our window to safely act and once I guaranteed to Officer Rivera that I could capture the hawk and safely contain it, he acted. After briefly halting all the eastbound freeway traffic for me, I was able capture the hawk and place her in the only animal transport carrier I had – a live animal trap. I know this is not the ideal carrier for a raptor (or any bird), but it was all that I had in my vehicle and a freeway hawk rescue was not on my list of things to do that day! With the hawk safely in my vehicle, Officer Rivera escorted me to the Yolo Fruit Stand where I met up with Yolo County Animal Service.

With the danger of the freeway behind us, we agreed I would take the hawk to the VMTH for evaluation.

Swainson’s Hawks are a state threatened species and populations are declining throughout much of their range. In the Central Valley, these beautiful birds arrive in early March or April to breed. The breeding season can last through August until they gather again to start fall migration. Most of these hawks winter in Mexico, Central and South America. This species is one of the many that is vulnerable to pesticide poisoning. Pesticide use in Argentina was responsible for the deaths of nearly 6,000 individuals in 1995-1996. CDFG has initiated a Swainson’s Hawk inventory in response to the listing and more information can be found at the California Swainson’s Hawk Inventory.

I am happy to report that this hawk was treated for soft tissue and head trauma at the VMTH and is now being cared for at the California Raptor Center.   I am hopeful that she will be released soon!

Thanks again to Officer Rivera for his exceptional professionalism and ability to control the situation quickly and safely – he helped to give this hawk a second chance! A big thank you goes out to Deana, Stella, and Krysta for their assistance.

CDFG does not advise anyone to risk their safety and the safety of others to care for sick and injured wildlife. If you should find an injured bird or wild animal, please visit CDFGs Living with Wildlife to learn more.

For more information about pesticide use and wildlife conflicts, please read A Sad End for a Coyote by WILs Stella McMillin.

Adult Swainson’s Hawk

For more information on Swainson’s Hawks or other wonderful birds in our area please visit All About Birds by Cornell’s Lab of Ornithology or the Seattle Audubon Societies Bird Web.

More information on wildlife rehabilitation and a complete list of wildlife rehabilitation facilities in your area can be found by clicking on the links.

Beware of Attack Blackbird!

Female Brewer’s Blackbird in flight at the regional office in Rancho Cordova.

If you live in the greater Sacramento area, chances are you’re familiar with the Brewer’s Blackbird.

These birds require open ground to forage on and dense vegetation for nesting, which makes urban areas prime real estate for a Brewer’s Blackbird community. Our regional office in Rancho Cordova is no exception!

We have a resident community of blackbirds year-round and currently we find ourselves at the peak of breeding season.

Our parking lot has become a source of amusement for passive onlookers as well as a source of humiliation to those at the receiving end of the blackbird attacks. While this behavior will eventually wind down as the season progresses, we caution anyone brave enough to enter our doors – beware of the attack blackbird … he has a nest to protect.

Spring is always a busy time of year for animals and the Wildlife Investigations Lab alike. Animals are not only becoming more active after a restful winter season, but many are also caring for young.

Blackbird couples are monogamous and both the male and female will care for their chicks, typically having 1-2 broods a year with a clutch size of 3-7 eggs. During this time, the male is extremely territorial and will harass, dive-bomb, and chase anything that poses a threat … including people!

Adult males are easily identified by their iridescent black plumage and bright yellow eyes. Adult females are a little more discrete and are a dull brown color with darker wings and tail.

These colonial birds are very habituated to people and are commonly seen roosting, nesting, and feeding in urban and agricultural areas.

A male Brewer’s Blackbird keeps a vigilant eye on passers-by at CDFGs Region 2 Office in Rancho Cordova.

For more information on the Brewer’s Blackbird or other birds in our area, please visit:

A nest of Brewer’s Blackbird chicks at the Region 2 office.

http://www.allaboutbirds.org/guide/Brewers_Blackbird/id

http://animals.nationalgeographic.com/animals/birding/brewers-blackbird/

http://birdweb.org/birdweb/bird/brewers_blackbird

Fish and Game would like to remind people to be wildlife aware. Please observe wildlife and their young respectfully and at a safe distance. For more information, follow the link:

http://cdfgnews.wordpress.com/2012/04/16/dfg-reminds-the-public-to-leave-young-wildlife-alone/