Wednesday, September 30, 2015

Weathering Storms

This summer was particularly wet. There was plenty of rain, thunder, and lightning, and while we were likely holed up in our houses, warm, safe, and dry, our wild feathered friends were outside. Although they might not have the luxury of a roof and four walls, birds have their own methods of surviving inclement weather.
A typical Midwest thunderstorm (photo: the wikipedia files)
First and foremost, birds take shelter during a storm. Fortunately most of our backyard birds are small in size, allowing them to take advantage of microhabitats. Hiding in the small spaces inside a hedge or on the lee side of a tree can make all the difference during high winds. Instead of being buffeted by driving wind and rain, a little bird will stay relatively warm and dry.

Preparation for storms is crucial, because birds will not be foraging for food during inclement weather; instead, they will devote their energy to staying safe and warm. Birds may be able to detect changes in barometric pressure, which would explain how they know to increase foraging activity before a storm hits. The extra fats and other nutrients that a bird acquires during this foraging give the bird a better chance of survival.

Of course, some storms are too severe for birds to safely weather. Tornadoes, for example, are so destructive that even taking shelter in microhabitats is not likely to protect a bird. The only sure way to survive a tornado is to avoid one – which is exactly what some birds do. A recent study on migration accidentally discovered that birds that had already returned from migration went out of their way to avoid a storm system that was producing tornadoes.

Warblers (a group of birds within the songbird order called Passeriformes) that had been outfitted with trackers showed something odd: the birds suddenly traveled 400 miles south of their breeding grounds. A day later, scientists noted a massive storm system moving towards the area the warblers vacated. Because the weather conditions were still normal as far as the researchers could tell, they are not entirely sure exactly how the birds detected the storm.   They believe, though, the warblers may have been able to detect the low-frequency sound that tornadoes produce. Such a deep sound, below the hearing capacity of humans, can travel well ahead of the storm and warn any animals that can hear it.

Mother nature can be fickle, and birds must be resourceful to deal with the variety of conditions that nature can throw at them. Especially in a changing climate, birds must be able to adapt, and ultimately evolve, or else perish.

Submitted by JoHanna Burton, World Bird Sanctuary Naturalist

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