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Accidental Airmail
- Vanderbilt University Press
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3 Accidental Airmail Dark branches spread against the predawn sky. Among them larger silhouettes —ospreys—perch in silence. Their heads swivel now and then— when something flies above the distant cliffs, or a ripple disturbs the lake surface below. These fish hawks have felt a subtle seasonal cue, and now their eyes pounce on every detail. There is a particular softness in the air that portends the appearance of mayflies. News of the impending hatch has spread past the lakeshore—out beyond the aspen and pine at the margin of the valley-bottom meadow. Eagles perched on granite crags are watching from the distance. Their sight is keen enough to count the black-and-white fish hawks as the sun lights the treetops. The eagles will soon move into position to crash this party. Below the water’s surface the first members of the hatch are already emerging from concealment. Mayfly nymphs—small, dark swimmers with long legs and lacy gills edging their bodies—climb the strands of algae and swarm over the rocks and snags on the bottom. Their internal clocks have been reset by changes in the water temperature that predict a day above the waterline well suited to the nuptial flights of adult mayflies. Most of these nymphs have long since been ready to emerge but have delayed. They were waiting for their final environmental cues while the slower growers among them caught up with the rest. Now the skin has begun to split along their backs, and they are moving up through the water column. Their synchronous emergence will maximize their chances of finding mates. They will appear all at once, in numbers that will confront their predators with an overabundance of prey—leaving most of the insects to survive. They will molt quickly on the surface, sprouting wings to carry them away from the feeding frenzy their appearance will evoke. On the shelter of the shore there will be more time for a second molt, which will produce the final, clear-winged adults. Trailing paired filaments longer than their bodies, the adults will be ready to take to the air the following morning—appearing as clouds of undulating motes that fill the sun gaps in the shoreline understory. They will drift out above the water, spinning higher, then dropping, finally mating. 4 Their brief adult lives will conclude as they spill millions of eggs back into the lake, assuring the continuation of their annual emergence spectacle. The trout are the first to notice the hatch. The rising nymphs are invisible against the bottom, but when they move up through the water, they draw the attention of the fish. When their targets emerge into view backlit from above, the trout rise in pursuit. Where the surface begins to ripple and boil with feeding fish, the ospreys stir into action. One osprey falls from her perch, converting height into speed as she dives for the water. She has singled out her quarry—one larger trout among the many that are rising all across the lake. But just as she begins her acceleration , the fish changes course with a flick of its tail and fades from view. So the fish hawk flares her tail and levels out, gliding on her momentum . She is low enough now to see fine details—the dimples on the water that mark mayflies riding on the husks of their nymphal skins as they dry their new wings, and ripples spreading from the places where those mayflies disappeared as the trout struck. The osprey wheels through a wide arc, and her turn brings another rising trout directly into her sights, even larger than her first choice. So she tucks back into a dive and builds upon the speed she carried from her initial descent. She is tightly focused as she plummets, accelerating as the fish enlarges in her eyes. When she hits the water, her foot will punch through the surface faster than the quickest trout could react. The osprey hits her target at forty miles an hour, her speed carrying her completely under but for the very tips of her wings. Her curved talons are longer than those of any other raptor, and scales on the soles of her feet taper to thorns that work like the fine back teeth behind the canines of her claws—her grasp is as fast as the bite of a barracuda. She emerges again before the splash has settled, holding her wings high. She beats against the...