I photographed this tricolored heron stationary in the bay water on South Padre Island. This is the area of the Laguna Madre that you see at the end of the boardwalk. This heron is bathing, and for good reason. A challenge for birds such as this heron is to control their salt intake. Salt is detrimental to their feathers, and even more deadly when taken internally in excessive amounts. Some birds have enlarged salt glands that allow them to remove salt extra-renally. The glands are located in slots on the forehead. Salt is removed by the glands, and it streams down a groove in the bill to the tip. Birds such as the ruddy turnstone and the sanderling are able to remove as much as their own body weight in salt each day. This heron, I suspect, isnt quite so adept at removing salt. The bath is critical to him (or her) osmoregulating. This area of the Laguna Madre is where the outflow from the treatment plant meets the bay. This is why the marshes that border the boardwalk are thick with cattail (Typha). Typha is not salt tolerant, and would not be expected along the hypersaline Laguna Madre. The fresh water from the treatment plant, however, has allowed it to become established.
Posted on: Wed, 04 Jun 2014 22:34:22 +0000
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