The Changing Faces of the California Brown Pelican

Mt wife and I stopped along the edge of Bodega Bay, on the California Coast, this past weekend, to enjoy some clam chowder and watch some seabirds.  As we sat and ate, a number of California Brown Pelicans were standing or sleeping on a floating dock nearby.  The different colors and patterns on the heads of these birds can reveal a lot about their age and breeding condition.  About half of the birds we were watching had the solid brown head and neck, even brown body, and white belly of hatch year birds.  Since the Brown Pelican breeding season is generally from March to July, these are birds that just hatched within the last few months.  Other birds had white feathers on their faces withe some brown speckling, and brown feathers down their necks.  These were the adult birds in their non-breeding plumage.  They hatched in the summer of 2011 or earlier.  The two birds were could see the clearest probably were in fact 2011 birds because their tails had feathers that were grayer adult feathers, but also stall had some brown feathers mixed in that matched the tail feathers of the hatch year birds.  These retained feathers had not been replaced during the first cycles of molt (large birds often have several “generations” of feathers at one time.  This is thought to be because of how much energy and resources it takes to grown so many large feathers.).  As the year progresses, the face of these adult Brown Pelicans will change just prior to the beginning of the breeding season to be a pale yellow color on the head and still have the dark brown neck.  After the breeding season their appearance will change again to the familiar pale yellow head and white neck.  The next plumage in the cycle is the brown neck with the white head and speckles that we saw in Bodega Bay.  We along the central and northern California coast do not see the plumage just before the breeding season very often because Brown Pelicans along the Pacific coast have a strange migratory pattern.  Where most migratory birds go south in the winter to rest and north in the summer to breed, California Brown Pelicans go north in the winter to rest and fish along the California coast and go south in the summer to breed in the Gulf of Mexico.

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A Natural History Calendar

I have now begun to officially keep a phenological record.  Phenology is simply the study of the timing of events in the annual cycles of plants and animals.  All the great natural historians (Aristotle, Darwin, van Humboldt, Carson, Thoreau, Huxley, Linnaeus, Wren, Audubon, Skutch) kept this kind of data.  They recorded when birds arrived or left on their migrations, when flowers bloomed, when the leaves fell, when ice formed and broke up.  Aldo Leopold, one of my personal heroes, was famous for keeping detailed records of all the comings and goings that took place at his farm in the Sand Counties of Wisconsin.  These records are now being continued by his daughter, and they form an incredibly detailed record of a wide variety of events.  Other groups also collect phenology data; for example, the National Oceanic and Atmospheric Administration (NOAA) has been compiling weather data for more than a century.  Collections of these types of data sets have been vital to the measurement of global climate change.  Only from having long standing and continuous records of when the first individuals of particular species of birds arrived in spring or when the first snows fell in the mountains can we observe and track the slowly changing variations that are occurring on a planet wide scale around us.

To add to this endeavor in some small way, I will be tracking the occurrence of events in Central California.  I am not even attempting to track every possible natural history event.  When weather, animals, plants and fungi are all considered, it is clear that this would be impossible.   Instead, my hope is to track some significant events from season to season and year to year, and to add more and more such events as time goes on.

My calendar can be found under one of the tabs on my blog’s homepage and also at:

http://www.google.com/calendar/embed?src=ucdavis.edu_fdnuk0mj4njqsf2bc5ks2qvma4%40group.calendar.google.com&ctz=America/Los_Angeles

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Bitten

I have been studying the Evening Grosbeak for the past three years for first my Master’s degree and now my Ph.D.  Studying this species has had many wonderful benefits.  Since they are commonly found in mountainous areas, I have traveled to, and camped in, many parts of the Sierra Nevada, Cascade, and Rocky Mountains.  I have met wonderfully generous people interested in the birds that share this world with us.  I have had the opportunity to glimpse some of the details of some aspects of the lives that members of this species lead.  However, one facet of working with this species that has not been quite so wonderful is the bite that these birds can deliver!  It is amazingly powerful!  I have been banding birds of many species for over a decade now, and in that time I have been bitten by quite a few birds.  I have been bitten by Cardinals, I have been bitten by American Kestrels, and I have bitten by Downy Woodpeckers just to name a few of the more painful species.  I have even been bitten by Black-headed and Blue Grosbeaks, which have a similarly shaped beak, though they are not actually closely related to the Evening Grosbeak.  None of those bites prepared me for the first time I was bitten by an Evening Grosbeak.  I was in Oregon on my first trip out to do field work on my project and had caught my first Evening Grosbeak in my mist net.  I was very excited and began spreading the net open so that I could untangle the bird.  Just as I was reaching my hand in to get a hold of the bird, it suddenly turned its head and clamped its beak down on my finger.  Wow, did it hurt!  If you take a pair of pliers, put the side of one of your fingers between the jaws, and squeeze tight, you will have some idea of what my finger was feeling at this point.  And not only do they have the strength to cause some serious pain, but they have the stamina to continue applying that crushing pressure seemingly indefinitely!  I reached my other hand in and tried to pull the bird away from my hand, but it would not let go.  I waved my other hand around near its head, which sometimes works to distract a bird, but it would not let go.  My eyes now watering from the pain, I even tried to pry the birds’ beak off of me with my other hand, but it would not let go!  Finally, it seemed to grow bored with my finger and let go and started screaming at me instead.  Over the next two days, I caught about 30 Evening Grosbeaks and many of them treated me to the same amazing bite!  By the end of my trip the sides of several of my fingers were black-and-blue with bruises from the repeated biting.

To give you a reference for what Evening Grosbeaks use their beaks for when they are not biting banders, they can sometimes be seen eating Chokecherry (Prunus virginiana) or Bitter Cherry (Prunus emarginata).  Like domestic cherry we all buy in the grocery store, these wild cherries have a very hard pit surrounded by a layer of soft fleshy meat.  Evening Grosbeaks carefully peel off the fleshy meat and then drop it on the ground.  They then take the hard pit in their beaks and crack it open to eat the tissue inside!  No wonder my fingers hurt!

Finding this our for my self, and watching others who have worked with me find it out for themselves, has actually been a very exciting process.  The only way to learn about a thing is to get close to it.  Sometimes this may mean closer than is comfortable, but it is only through this closeness, this intimacy, that true understanding is gained.  As my research on these birds continues, I am looking forward to learning many more little facts about them, and so to coming ever closer to true understanding.

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Some Notes on the White-faced Ibis

I was out walking at the Yolo Bypass National Wildlife Refuge, yesterday, and was treated to the sight of a flock of about 30 White-faced Ibis flying overhead. This is one of the species that I always look forward to seeing in the summer, here in Central California. They are beautiful and elegant birds, and seeing them always seems somewhat exotic feel, like you are in the tropics somewhere. The breeding range of this ibis is highly variable from year to year depending on water levels and food availability. Large numbers may nest in a general area one year, and none may be there the next. The total range that they can potentially breed in encompasses a huge area of the western U.S. This makes monitoring of their population levels rather hard because any survey would have to regularly cover the entire potential breeding area to accurately count the actual number of birds in any given year. No small task! Due to the fact that the White-faced Ibis often feeds in agricultural lands, they may be exposed to many of the pesticides and fertilizers that are used in growing our food. This heightened exposure potential makes them a possible “canary in the coal mine,” and so a particularly important species to monitor. This species’ winter range mostly resides in Mexico, and little or nothing is known about this part of their annual cycle, a fact that is true of so many bird species. A wonderful bird that I hope you all can get out and enjoy before they head south in a few weeks!

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Cattle Egrets on the Move

I have been seeing lots of Cattle Egrets around Davis the past couple of weeks.  Before a couple of weeks ago, I did not see any moving through the skies over Davis, but now I am seeing them frequently.  They have been in groups that range in size from five or six up to flocks of 25!  Very beautiful birds.  From what I know of their annual schedule, some should be starting to molt (if they started breeding early in the season and have already fledged their young) or still have young birds to feed (if they started breeding later in the season).  So, I am guessing that the groups I am seeing are family groups of adult and juvenile birds or perhaps a few family groups that have merged together.  Cattle Egrets are very successful dispersers.  Originally native to Africa and southern Europe, they are now found on every continent except Antarctica and also on many remote islands, and they have done so without human intervention crossing from Southeast Asia to Australia in the 1930s and crossing the Atlantic Ocean from the west African coast and making landfall in northeastern South America in the late 1800s.  The first recorded breeding pair was in Florida in 1953.  In South Africa, where their population is generally sedentary, individuals or small groups of juvenile birds have been frequently observed to go long distances when leaving their natal area in search of new breeding areas.  This behavior is common to many of the Egrets and Herons, but it is especially well developed in the Cattle Egret and it seems to be one of the major factors that have allowed them to cover the globe.  In fact, the dispersal of individuals across large bodies of water is probably still occurring because these birds are regularly seen be passing ships far out at sea.  With so many examples of species being introduced by humans into new areas, I think it is really cool and interesting to see an example of dispersal happening naturally, as it has been happening for millions of years.

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Eurasian Dove Invasion

My wife and I just returned from a short trip to Ashland, OR and surroundings.  It was a great trip filled with Shakespeare, rain, hiking and birds!  We have visited this region every year for several years now, and this year there was a new arrival there waiting for us…Eurasian Collared-Doves.  Lots of them!  This non-native species has been spreading quite dramatically across North America in recent years.  A small, but growing, population has been breeding in Davis, CA for the past few years.  The existence of this species in North America is largely the result of escaped birds that decided not to return to their cages.  As a result, this invasion started in large urban areas.  In California, San Francisco, Los Angeles, and San Diego were the first locations that reported having feral groups of these birds.  The range that this increasing population covers has been growing faster and faster, and this is the first time I have seen them in southern Oregon.  They were all over Ashland and Jacksonville and the smaller towns in between.  How this species interacts with the native Mourning Dove or Whtie-winged Dove, or the fellow invasive Rock Pigeon has not been studied, but it seems that these species have close enough natural histories that interactions will occur, and since the Eurasian Collard-Dove population in increasing, it seems likely that some or all of the others are suffering.  So, keep an eye out for this large pale-gray dove, and also take time to notice how many Mourning Doves you see around.  The earlier we can catch on to a possible problem, the more likely we are to be able to influence the eventual outcome.

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