From the BCDC Western Outpost - In the path of Crows

     I’ve always had a casual interest in crows. Primarily for their social structure and intelligence. But I, like most people, have taken them for granted over the years. This all changed soon after our arrival in Southern California.

     We were introduced to the Murrieta Crows Roost early after our California arrival in late 2009. While we were looking for a home we rented an apartment in Murrieta, CA. The apartment complex is located adjacent to the Murrieta Retention Basin. The retention basin contains water year round and is host to the largest contiguous forest of large trees in the area. The trees extend into the apartment complex area and our unit was located under a number of large trees. The retention basin is a terrific birding spot with a trail around its perimeter but the area doesn’t attract a lot of birders since there is a lack of parking in the area.

Murietta Retention Basin

     It’s easy to see that the large tall trees (pines, sycamores, eucalyptus, and others) provide the perfect place for a communal crows roost.

     It rained for three straight days when we moved into the apartment and nothing out of the ordinary occurred, although the local residents thought three straight days of rain was quite “unusual.” At sunset on the fourth day we heard a lot of crows calling. We went out on the patio to see what all the commotion was about. It was quite a surprise as “calling” crows dropped into the trees by the hundreds. The crows would sit for a while then rise up and put down again. This went on for some time before they all settled down in the trees for the night. At sunrise the next morning all the crows were gone.

     I asked some of the other residents of the apartments whether this was a regular occurrence and they casually responded, “Yeah, it happens every night!” From then on we witnessed the evening event on a regular basis making sure to get under cover on their arrival. It was common for the crows to “dump their excess baggage” before settling down.

     A month and a half later we found a home five miles north of the Murrieta Retention Basin. We moved into our new home under a steady two days of rain. Our new welcoming neighbors remarked about the “unusual” amount of rain. During a downpour our first yard bird at our new home ran around on our front lawn occasionally posing on a boulders. The Greater Roadrunner welcomed our arrival. I took this event as a harbinger of more good birding things to come.

Greater Roadrunner

     After settling in to our new home, I had more time to start renewing my acquaintance with the western birds and to begin creating my new yard list. I also had time to enjoy the cool evenings in the backyard and immediately became reacquainted with the crows once again. Our new home is located “in the path of crows” that fly to the communal roost each evening from the north to the roost five miles south.

     Since first witnessing the crows roost and now living along the northern route of the crows, I have become interested in learning more about the nature and structure of the roosting crows. Apparently there is little known with regards to why, when, and where crows decide to share a common roost.

     The website crows.net lists the number of crows at the Murrieta Crow Roost to be in excess of 3,000 birds. The site also indicates that there are only two crow roosts in Southern California.

     I have been at different locations in the Temecula/Lake Elsinore valley in the evening and have observed crows flying to the roost from all different directions. It appears that the northern component (the ones that fly over us) make up at least one third to perhaps one half of the total roost population. This would make sense since Lake Elsinore and the area north of the roost site is more rural than south and east of the roost site. The area west of the roost site is the Santa Rosa Plateau small numbers of crows heading east to the roost at sunset.

Crows at sunset

     I have conducted a number of crow flight counts to get an idea and to see if there are any patterns that might be of interest occurring. During the 2012 Christmas Bird Count, I counted 1,268 American Crows (AMCR) heading to the roost. During a BIG SIT in 2011, I counted 1,195 AMCR heading to the roost. I also conducted a 12 day count in 2011 which resulted in a 12 day average of 664 AMCR (9 days of 500 or more, and 2 days of inclement weather). Just this past week I was up early to photograph the full moon setting before sunrise – during that time I count in excess of 700 AMCR heading north from the roost site.

PHOTO – Crows passing under the moon 

Crows passing under the moon

     It appears that there are three or four distinct flocks coming through each evening from the north. The first flock passes through just before sunset, the second flock shortly after sunset, and the third and fourth flocks closer to dark. There are always a few stragglers bringing up the rear. I’m guessing that the distinct flocks may be related to the distance the crows are from the roost when they initiate their flight (the first flock – closest to the roost, the remaining flocks- further away).

PHOTO – Crows at sunset-02

Crows at sunset

    The crows roost essentially ceases to be during the breeding season with the exception of a few non-breeding birds that continue to fly to the roost each evening. Soon after the breeding season ends and the young have fledged the numbers heading to the nightly roost start picking up again. During this time there is a lot of “calling” among the crows during the flight to the roost, perhaps the parents trying to keep the youngsters on task.

     There appears to be a pre-flocking process that is used from time to time. Prior to initiating their flight to the roost the crows first gather at a staging area. A lot of “calling” takes place during this process and at some point a command is given and the flock of crows begin heading towards the roost site in silence. The staging areas appear to be random and may not be used on a daily basis. The purpose for these staging areas remains unexplained but may be weather related or perhaps staggering the flocks so they don’t all arrive at the roost at the same time.

Crows in stormy weather

     The line of flight of the crows each evening is weather dependent. Generally from our vantage point we can see most of the crows heading to roost each evening even if the flocks choose an alternate route. During inclement weather or heavy winds the flocks may be hard to see. The crows fly low in the valley and blend in with the trees along Murrieta Creek.

     We are very fortunate that our new home in Wildomar, CA provides us the rare privilege of witnessing nature’s free outdoor entertainment almost every evening.

Jim Lockyer

Wildomar, CA

BCDC WESTERN OUTPOST

HAWK WATCHERS COUNTING MORE THAN RAPTORS

                     Helping Researchers Study Dragonflies

Eastern Pondhawk

        Dragonflies are, in my opinion, tied with hummingbirds as the coolest fliers ever.

        I recently listened as Dr. Michael May, a retired Rutgers University professor of entomology, spoke to a small group of raptor enthusiasts hosted by Dr. Laurie Goodrich at Hawk Mountain Sanctuary. Goodrich is Senior Researcher for Hawk Mountain Sanctuary and Assistant Chair of Hawk Migration Association of America. May’s topic was unfamiliar; he spoke about dragonfly migration, a relatively new and little studied field.

        The unique dragonfly study is being undertaken by the Migratory Dragonfly Partnership, a small group of government and private organizations from Canada, Mexico and the United States. The Xerces Society is coordinating the cutting-edge program; they are involved with the conservation of invertebrates.

Partnerships determine much of the success of wildlife conservation. The Feds partner with states, and states partner with counties, as well as with: local, state, national and international conservation groups. Many wildlife species are difficult to work with, in part because some species migrate across state and international borders; dragonflies cross United States north and south borders.

            Dr May provided additional information during my follow-up phone call. When asked, “What’s the purpose of trying to determine the migration routes of dragonflies”, May answered simply, “We want to study dragonflies because of their beauty and aesthetics.”

May’s statement’s simplicity stopped me in my tracks because his answer is pretty much why I spend so much time watching raptors. The miracle and mystery of both dragonfly and raptor migration can be added to our particular interest.

May said dragonflies have a place in the food-chain, and in different situations dragonflies have either more or less importance. Nevertheless, dragonflies are a plus in nature, and lovely to observe.

Here is a basic life history of the dragonfly. Adults lay eggs in ponds, preferably in ponds with very few fish. Eggs hatch into larvae, and some live underwater for five or six months, though one year is more typical. Since fish eat dragonfly larvae, fewer fish in the pond mean more larvae morph into adult dragonflies. After the larvae morph into dragonflies and live seven – ten days, the newly created adult dragonflies are able to breed. After breeding the female lays her eggs in fish free (hopefully) ponds and the cycle of life continues. Some dragonflies migrate and some do not.

        Now things get complicated, even for May, though it is not his fault. The problem is caused by lack of information, just the kind of information May is hoping to get from hawk-watchers, as well as entomologists.

           Adult dragonfly’s lifetimes are not totally known because many species migrate and leave their birthplace. The problem starts because different species travel different routes and distances to different regions.

        The wintering place for migrating monarch butterflies was unknown for years. Now it is known that most of “our” monarchs’ winter in a small area of mountainous Mexico. There has long been concern among scientist that if a serious weather event hit the monarch’s wintering home, most-to-all monarchs could be destroyed. A catastrophe!

        “It is a benefit having dragonflies winter in different regions so an extreme winter in one region wouldn’t kill them all,” said Mays, “but it would also help to have a better idea just where they are,” he said with a chuckle. That is what he hopes to discern from hawk-counters.

        May, Goodrich and their associates’ hope that hawk-counters at various hawk-watches can count and report migrating dragonflies they observe.

        Using newly created data sheets, counters will record and report dragonfly numbers starting during this fall’s raptor (now) migration. Both their raptor and dragonfly reports will go to the citizen scientist from the Hawk Migration Association of North America. HMANA’s data is used by scientist, researchers and raptor lovers worldwide. The dragonfly data will go to the Xerces Society and their partners. The partnership plans to track five dragonfly species.

        Dragonflies captured on their wintering grounds can indicate where they were born by testing isotopes found in their body. The captured migrating dragonfly’s isotopes will determine where aquatic plants eaten by the water-bound larvae stage of the dragonfly was found. Scientists can map those locations, at least in terms of longitude (north and south). It’s pretty slick, actually.

        May suggested interested naturalists look at: Dragonflies Through Binoculars, by Sid Dunkle, and Dragonflies of the East (U.S.), by Dennis Paulson for assistance identifying dragonflies.

        Goodrich finished, saying, “HMANA will do a pilot dragonfly count program this fall, and willing hawk-watchers will count and record dragonflies seen. It will be tweaked as we progress, and flexible.”

                               

For more, see: www.migratorydragonflypartnership.org; www.hmana.org.

ACADIA BIRDING FESTIVAL

ACADIA BIRDING FESTIVAL
by Donna Chadderton

    In late May, two of us attended the 15^th annual Acadia Birding Festival on Mount Desert Island, Maine.   Many field trips were offered over a four day period that included morning and afternoon hikes, canoe trips, van trips, and boat trips, including one pelagic trip that was dedicated for festival participants only.  A wee hour of the morning owl prowl was also available.  The field trips were located within Acadia National Park, outside the park but still on MDI, and mainland boreal areas to the north of MDI.  This allowed for a wide variety of habitats to be explored – pelagic, coastal, meadow, and forest.  In addition, afternoon workshops were offered that covered smart phone apps, birding-by-ear, seabird and general bird ID, and e-bird.   Most of the hikes were flat to moderate.  One could sign up for any event that was of interest, as long as it wasn’t already at capacity.  (The van trips had a limited number of seats, which filled quickly).    There were evening presentations by two guest speakers, as well as a lobster cookout at a local lobster pound.  A silent auction was also held at the festival center in Somesville.  Birders of any skill level are welcome at the ABF; and the guides are knowledgeable and friendly.   Just a few of the 150 species of birds that were observed during this year’s festival included Blackburnian Warbler, Black-throated Blue Warbler, Roseate Tern, Atlantic Puffin, Razorbill, Black Guillemot, Sooty Shearwater,  Common Loon, and Barred Owl.  The data collected were submitted to the citizen science database, e-Bird.

     Mount Desert Island is a great place to visit because it has something for just about everyone. The town of Bar Harbor bustles with tourists during high season, but the ABF occurred before the summer crowds descended.  Bar Harbor is also a casual town and full of family friendly activities.  Acadia National Park has breathtaking scenery, miles of trails, and many opportunities for exploration outside of the Acadia Birding Festival.  This was a wonderful, educational, and worthwhile trip.  The included photo was digiscoped during the 2012 festival.

Common Loon

Birding in Northern Lower Michigan (Leelanau County) in July 2013

                                                              Authored by Sara Busch

     I recently returned to my roots and visited Leelanau County in Michigan’s Lower Penninsula in July.   Of course, I had to move away and develop an interest in birding in order to appreciate the raw and gentle beauty of “The Leelanau Pennisula.”  To make matters worse, it was only after moving to  Delaware County Pennsylvania that I found out that the rare Kirtland’s Warbler was practically a childhood neighbor in Michigan.  Alas, this short weekend visit did not include a trip to the Kirtland’s habitat.  But, it did provide some spectacular weather for bird walks!

The Sleeping Bear Birding Trail offered a local bird list, but unfortunately could not provide me with any organized bird walks that I might be able to join during our visit.  (So grateful for all of the field trips and bird walks the BCDC offers!)  Here are a few pictures of some of the birds and scenes I was able to enjoy one morning, in the great Up North. 

  

                                                                  Thank You Sara