By Don Welty
Winter here in the Wrangells comes early, and leaves late. The vast majority of our diverse bird population migrates out of the area, leaving a few hardy species behind to brave the long winter. Much to the delight of us winter residents, grosbeaks, chickadees, redpoll, woodpeckers, jays, grouse and ptarmigan are a few that choose to stay in the area.
Many of the migrant birds embark on long, seemingly impossible journeys to their wintering grounds. One such bird is the golden plover (Pluvialus dominica). This small shorebird has long distance cross country flying skills that make us pilots look like “bird brains.”
Adult plovers arrive in Alaska in May and June, making their nest in dry tundra or tussocks. Both parents tend the three to four eggs until hatching, 26 days later. The male then leaves, with the female staying till the chicks can fly 23 days later. The female then leaves the young to fend for themselves, following the male to their wintering grounds in Hawaii and Polynesia. The young feed on insects, (no shortage of those here in the summer!) crowberries, and blueberries, fattening up for the long journey ahead.
It is beyond our comprehension how the adults find their way to Hawaii across 2300 miles of open sea. Even more how these young birds find their way, having never been there or having adults to show them. With nowhere to land, being unable to swim, the birds are not capable of making the long non-stop flight with the available fat reserves.
How then do they ever make it? The birds somehow know to flock up with other juveniles and hold a v-formation, allowing them to increase flight efficiency by 23% over solo flight. They somehow also know to fly at the optimum, energy efficient speed, according to their particular weight and shape. This gives them an impressive weight to fuel consumption rate twenty times more efficient than our flying machines.
Eighty eight hours and 250,000 wing beats later these inexperienced aviators reach the Hawaiian Islands. It is still unknown how the birds know how much fat is needed for the trip and how to arrange to have this precise amount at the proper time. It seems they are able to calculate distance and specific rate of fuel consumption for a place they have never been.
Even more impressive is their system of navigation. Only a 5 percent error and they miss the island, this is not a process of trial and error. Without maps or compass, G.P.S., or flight instruments this juvenile “bird brain” finds its way over 2300 miles of featureless sea, continuously compensating for wind speed and direction, darkness and adverse weather. The question of how these birds complete this “mission impossible” remains unanswered.
A large number of disorientation experiments have been carried out with homing pigeons in an attempt to understand how birds accomplish complex navigation. This bird’s navigational capabilities extend beyond the bounds of our imagination. Even when birds were anaesthetized for the outward journey, or if their cages were rotated continuously, they were able to return home from far away. Simply having a sense of direction is not enough for this type of navigating; they have to have a sense of geographical location relative to their home territory. The tendency to drift off course due to winds must be compensated for continually to fly a direct route. Merely homing in would not compensate for wind drift and would lengthen the route, as many beginning pilots learn. In the case of the plover, such a curved course could prove fatal. Similar to an autopilot, they seem to be able to sense and adjust throughout the trip. Just where this autopilot is located in the bird, and how this information for operating is coded, is not known.
Birds are truly an image of God’s creative power, invisible attributes, and eternal power (refer to Romans 1:20). A real stumbling block to evolutionary thinking with the incomparable feather, unique respiratory system, and “autopilot,” just to name a few. The challenge to evolution does not come simply from a few fanatics, but from the study of nature itself, defying man’s self-proclaimed wisdom. “Even the stork in the sky knows her appointed times; and the turtle dove, the swift, and the swallow observe the time of their coming, but my people do not know the judgement of the Lord.” (Jeremiah 8:7) Get to know the creator, bypassing this judgement, through faith in Jesus Christ, giving thanks for this wonderful world around us.
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Check out websites 5 and 6 for more information!
