Sunday, March 13, 2016

Who are you calling yellow-bellied?

First day of Daylight Savings Time today-- first day of spring and the vernal equinox but one week away.  Time to celebrate.  Perhaps time to think about those species that keep our natural world moving along. 

The yellow-bellied sapsucker, Sphyrapicus varius, is one of those forces of nature.  It is considered a ‘keystone’ species, as it plays a vital role in the ecology of bird life.  As the name suggests, sapsuckers get much of their nourishment from sap that they obtain from drilling well holes in trees in early spring.  They drill neat horizontal rows of holes or sapwells into the tree’s xylem or inner part of the trunk to feed on the sap moving up to the branches at the beginning of spring.  Many other species, especially migrating hummingbirds, kinglets, warblers, and phoebes time their migration to the arrival of the sapsuckers.  Those birds make good use of the sapwells living off of the sweet food before flowers begin to bloom and insects begin to hatch.  Like other types of woodpeckers, sapsuckers also eat ants and spiders that live beneath a tree’s bark and other insects that fly by.  They also like fruit trees both for their sap and for their fruit.  But their favorite trees seem to be birches and maples, not so different from us and our enjoyment of sweet maple syrup. 

The relationship between the sapsucker and the hummingbird is a curious one.  The sapsuckers provide the food and the hummingbirds provide-- well, not much, perhaps gratitude with its own interesting expression.  Some researchers have observed that if a sapsucker is attacked by another bird near the sapwell, the feisty little hummingbird comes to the rescue, fighting off the hostile intruder protecting the sapwell and the sapsucker at the same time.  On the other hand, the sapsuckers have been known to chase off hungry hummingbirds as well.  As I said, a curious relationship. 

Speaking of relationships, sapsuckers are playful daters.  They chase each other around tree trunks.  Courting birds face each other with raised bills and tails, fluffed out throats and crest feathers, along with wild swinging head movements.  Quite a way of getting someone’s attention.  It seems to work.  When they mate, they stay together through the nesting season and the raising of the offspring and often reunite in the next breeding season.  And with a somewhat New York City property mind, they sometimes seem more tied to the nest tree than to the partner, but since the partner may be equally home-minded, they stay together. 

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