My heart soared as the neon-yellow and jet black male hooded oriole fluttered into the nectar feeder dangling not more than 3 feet away just outside the window.
He glanced about nervously before dipping his beak into the nectar and then dashing away as if on an important mission.
This was the first oriole of the season and as far as I was concerned, his mission was complete, arriving here last week after traveling as much as 2,000 miles from his winter home in Mexico. These colorful and comical birds will brighten our gardens throughout the summer.
A few feet away, a chattering flock of white-crowned sparrows pecked at wildbird seed in a hanging basket. It was such fun to see both summer and winter visitors sharing the same space. Soon the sparrows and winter warblers that arrived in late September will begin a journey north that extends to the arctic slopes.
San Diego County is a birding paradise, considered to have the highest population of bird species in the nation, numbering around 520.
There are several reasons for this.
First is our unique habitat. We have it all, ranging from ocean, bays and marshes to inland lakes, chaparral forests, oak woodlands, broad grasslands, forested mountains and arid deserts.
Next there are migrations that bring different birds here seasonally. Some stay for months and others we briefly enjoy while they are ing through.
Migrations can be a roller coaster for nature lovers with sadness as the seasonal visits end for one species, and joy when the new birds show up.
Bird migrations also offer mysteries that have fascinated those close to nature for centuries.
Why do birds migrate, what determines the timing and how do they know where to go, are just a few of questions that avian scientists have tried to answer.
Seeking some insight into these mysteries, I reached out to Andrew Farnsworth at New York’s Cornell Lab of Ornithology. It was his fascination of migrations that led him into a career as an avian scientist.
He seemed to understand when I used the term, “mystery of migration.”
“There are several related schools of thought on what drives migration, but at some ultimate level, migration is a response to the changing patterns of the resources they need, like food or breeding habitat that follow the seasonal movement of the sun’s energy,” Farnsworth said.
His work has been devoted to tracking these patterns.
Such things as the change in the availability of food, or rapidly warming temperatures will trigger migration when necessary.
Then, Farnsworth said, there are those species known as calendar migrants that experience physiological changes that trigger migration as day lengths change.
Here, we see the arrival of hooded orioles each spring generally in the first two weeks of March. The famous swallows of Capistrano reportedly arrive annually on the first day of spring. This is such a dependable calendar event that the city has declared itself a bird sanctuary.
Like clockwork, the black-headed grosbeak will be arriving any day now from their winter homes in central and southern Mexico. They are known for their punctuality, arriving in the last few days of March.
Not all sudden arrivals are migrants.
An example is the jet-black silky flycatcher known as a phainopepla. Typically, this is a desert resident, easy to spot in mesquite thickets with its prominent topknot. In warmer months, however, it can be found in coastal areas and inland oak woodlands, likely escaping the withering desert heat.
Bushtits are another species that may suddenly appear in your garden.
This is our smallest songbird and an energetic little fellow that shows up in flocks of several dozen in fall and winter. They are resident birds but during most of the year gather only in pairs for nesting and breeding, making them less obvious.
One of the most exciting long-distance migrations is the journey of the Swainson’s hawk that is now ing through the eastern portions of our county.
Their spring journey begins near the southern tip of South America where they winter, and some will travel to arctic slopes of Alaska for the summer.
One of their waypoints is Borrego Springs where thousands are counted by volunteer hawk watchers from March to mid-April.
Bird numbers fluctuate each year, depending on available food because of winter rains. This year, numbers are high with nearly 400 launching in the mornings to catch friendly wind current that will assist them on their northward journey.
Navigation on these long migrations is both personally fascinating and scientifically challenging for Farnsworth.
“For navigation, birds likely have a program of sorts. A ‘map’ that may be akin to a series of rules such as ‘orient in this direction when conditions or photoperiod suggest; fly for a certain amount of time, stop,’ or something like that,” Farnsworth said. “Depending on the species, and perhaps just depending on the situation, we don’t really know much about this yet.”
There are more questions than answers about the mysteries of migration.
“Personally, regarding the mysteries I find the patterns and processes to be simply spectacular, and I also vacillate between awe at the magnitude and complexities of the journey and the realization that these organisms are built and fine-tuned for this.” Farnsworth said.
His human perspective allows him to see the almost unfathomable scenario of flying nonstop for more than a week on a journey nearly a third of the circumference of the Earth.
“But then, as a biologist I see the fine tuning of tactics and strategies that have worked,” Farnsworth said.
Redundant cue systems of celestial, magnetic, visual, acoustic and meteorological senses, along with highly efficient respiratory, digestive and other physiological systems, have worked multiple times over the course of birds’ lifetimes.
“A seemingly ordinary occurrence without fanfare,” he said.
Except for the fanfare from those of us who thrill at the sight of our traveling feathered friends.
Cowan is a freelance columnist. Email [email protected] or visit erniesoutdoors.blogspot.com.
