Sloshing Through Marshes to See How Birds Survive Hurricanes
upstart writes in with an IRC submission for Runaway1956:
Sloshing through marshes to see how birds survive hurricanes:
Clapper rails[*] typically live in tidal marshes where there is vegetation to hide in and plenty of fiddler crabs, among their frequent foods. Because they are generally common and rely on coastal marshes, they are a good indicator of the health of these coastal areas.
Water levels in tidal marshes change daily, and clapper rails have some adaptations that help them thrive there. They often build nests in areas with particularly tall vegetation to hide them from predators. And they can raise the height of the nest bowl to protect it against flooding during extra-high or "king" tides and storms. The embryos inside their eggs can survive even if the eggs are submerged for several hours.
When a tropical storm strikes, many factors-including wind speed, flooding and the storm's position-influence how severely it will affect marsh birds. Typically birds ride out storms by moving to higher areas of the marsh. However, if a storm generates extensive flooding, birds in affected areas may swim or be blown to other locations. We saw this in early June when Hurricane Cristobal blew hundreds of clapper rails onto beaches in parts of coastal Mississippi.
In coastal areas immediately to the east of the eye of a tropical cyclone we typically see a drop in clapper rail populations in the following spring and summer. This happens because the counterclockwise rotation of the storms results in the highest winds and storm surge to the north and east of the eye of the storm.
But typically there's a strong bout of breeding and a population rebound within a year or so-evidence that these birds are quick to adapt. After Hurricane Katrina devastated the Mississippi Gulf Coast in 2005, however, depending on the type of marsh, it took several years for rail populations to return to their pre-Katrina levels.
[*] clapper rails (Rallus crepitans).
Journal References:
- Scott A. Rush, Eric C. Soehren, Mark S. Woodrey, et al. Occupancy of select marsh birds within northern Gulf of Mexico tidal marsh: current estimates and projected change, Wetlands (DOI: 10.1672/08-174.1)
- Scott A. Rush, John Rodgers, Eric C. Soehren, et al. Spatial and Temporal Changes in Emergent Marsh and Associated Marsh Birds of the Lower Mobile-Tensaw River Delta in Alabama, USA, Wetlands (DOI: 10.1007/s13157-018-1082-x)
- Scott A. Rush, Jill A. Olin, Aaron T. Fisk, et al. Trophic Relationships of a Marsh Bird Differ Between Gulf Coast Estuaries, Estuaries and Coasts (DOI: 10.1007/s12237-010-9281-6)
- James P. Kossin, Kenneth R. Knapp, Timothy L. Olander, et al. Global increase in major tropical cyclone exceedance probability over the past four decades [$], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.1920849117)
Ehrlich, Paul, Walker, Brian. Roundtable: Rivets and redundancy [open], BioScience (DOI: 10.2307/1313377)
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