Robin invasion: Red-breasted birds no longer a harbinger of spring

Given the recurrence of ultra-cold spells and some snow this month, it’s probably safe to say that for most spring cannot come soon enough. (Exceptions like me, not surprisingly, are die-hard snow lovers willing to endure more of the same as long as there is still a chance of “big one”, i.e., until about the latter half of March.)

Snowy owls have been dominating the news of late, but I was extremely surprised to have a flock of at least a dozen red-breasted singing robins appear outside my condo in Southwest D.C.  this week. Until then, I took as a matter of faith that robins were a harbinger of spring, yet temperatures were in the teens with some snow on the ground.  I suspect I’m not alone in believing that sighting of robins bursting with song is symbolic of impending spring.

Snowy owl in my yard in SW D.C. (Steve Tracton)

Robins outside my condo in SW D.C. (Steve Tracton)

I’ve since learned this had once been true, but no more.  How could I (you?) not know this?  For me, at least, it’s been an article of faith that robins migrate south like most birds as winter approaches and return north as spring warmth begins to take hold.  So much for my highfalutin education and experience in weather/climate-related high profile natural phenomena.

In fact, as exemplified by a study in Illinois , nearly all robins did migrate as such until the late 1940s. Since then, robins wintering in the north increased through the 1980s followed by a very significant surge over the most recent two decades.

Ah hah! It must be the trend to milder winters due to anthropogenic global warming (on average). Fuhgeddaboudit!

According to Mike Ward, an avian ecologist who contributed to the Illinois study, birds don’t need to migrate to avoid cold. They just need to be able to eat enough to maintain their high metabolism until the return of their primary food source, earth worms and insects. Most important for enabling robins to spend winters farther north is availability of new sources of winter food, namely the spread of abundant berries of exotic, invasive shrubs that remain on branches through the cold of winter.

One especially significant example is the common buckthorm, one of which I’ve just found in the small tree next to my driveway.  Robins have been gorging themselves there with berries. Since this is the first time I’ve seen this, I assume they’ve been able to find comparable sources of berries elsewhere in previous years. One possibility is their need for drinking water. With ponds and backyard bird baths frozen by the unusual extended period of excessive cold, sources of water may be hard to come by.

Coincidentally, my wife leaves a bird feeder and plant holder on the patio with a heater to keep the water from freezing. Only occasionally does this attract a random bird or two, which I just assume are stragglers left behind as their kind migrate south in the fall. Robins do not eat birdseed, so I presume it’s the combination of the berries and drinking water that draws them here. (BTW:  robins avoid bathing in the water to keep their wings from freezing – the ground crew here has no deicing equipment).

Map of “Wave of Robins Seen, Spring 2014” (from:                                     http://www.learner.org/jnorth/maps/robin_wave_spring2014.html )

Map of “Wave of Robins Seen, Spring 2014” (from: http://www.learner.org/jnorth/maps/robin_wave_spring2014.html )

The arrival of robins outside my home is not an isolated event, as seen in the map (above) of first sightings. I have no specifics on the food and water at the other sites.

Have you seen any flocks of red breasted robins?  They are a wondrous sight to behold while listening to their variety bird songs, especially in the throws of bitter cold and snow. If so inclined, you can report your sighting here.

As for a harbinger of spring, look elsewhere.  For example, watch for bright colored crocus poking up to daylight, croaking frogs in the many local wetlands, Canadian geese flying in their tell-tale V formations trumpeting their unmistakable honk, honk, and of course the beginning of baseball’s spring training.

Also on Capital Weather Gang

D.C. area forecast: Arctic air retreats, but wintry worries don't disappear for long