Falling Warblers and the "Human Glacier"

Many species of songbirds fly non-stop 600 miles north across the Gulf of Mexico in their spring migration.  

 

Painted Bunting, Boy Scout Woods, High Island, TX

In prevailing conditions, most leave the Yucatan in the evening and arrive on the Texas coast the next day.  Many do not stop, but continue further north to the woods of East Texas or beyond.

 

Black-throated Green Warbler, Smith Oaks, High Island, TX

However, a strong cold front crossing the coast can subject the migrants to adverse headwinds and turbulence.   The exhausted birds "fall out" on the immediate  coast.   

 Chestnut-sided Warbler

Other birders have told us about days past when birds covered the ground and filled the bushes, seemingly unaware of human and other dangers.  Alan Tennant in his book On the Wing[1] gives a particularly vivid description of the "fallout" at High Island, TX and the carnage produced by speeding vehicles on the coastal highway.   

 

Kentucky Warbler, Hooks Woods, High Island, TX

In the past three years we have enjoyed birding the spring migration at High Island, TX.  But, we have seen nothing that matches the passage in Tennant's book, or the descriptions of the fallouts of past decades by other birders.  

 

Golden-winged Warbler, Boy Scout Woods, High Island, TX

This Spring, there were some days when various warblers, thrushes, oreoles, etc. were relatively abundant.  However, there were few days with strong cold fronts or significant northerly winds.  The "good news" in this is that migrant mortality is probably lower proportionately than in the past.  The "bad news" is that the few birds seen are only the remnants of once more abundant populations [2].  This is due to an overwhelming loss of habitat in breeding and in migration stop-over sites under inexorable "development".   The "human glacier that now bears down on every continent of the world" in Alan Tennant's metaphor.   

 Yellow Warbler, , Boy Scout Woods, High Island, TX

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[1] Tennant, Alan (2005) On the Wing: To the Edge of the Earth with the Peregrine Falcon. Anchor Books 304p.   (This is a great adventure book on an radio tracking a Peregrine Falcon by light plane.  The fallout of songbirds is described on p. 21-22 of the latest edition.)

[2] Cerulean Warbler populations, for instance, have fallen to less than 1/5th of what they were 40 years ago.  Wood Thrush populations apparently show a long term average decline of 1.7% per year.

Cerulean Warbler (wet in "drip"), Boy Scout Woods, High Island, TX

Bay-breasted Warbler, Boy Scout Woods, High Island, TX

American Redstart, Boy Scout Woods, High Island, TX

 Canada Warbler, , Boy Scout Woods, High Island, TX

Tennessee Warbler, Tropical Birding, High Island, TX 

 Black-and-white Warbler, , Boy Scout Woods, High Island, TX

 

 

Common Yellowthroat, , Boy Scout Woods, High Island, TX

Rats and Raptors - They're Back...

A few weeks ago, on a Galveston Featherfest field trip, we had an exceptional opportunity to observe a White-tailed Kite hunting in the fields near the North Jetty on the  Bolivar Peninsula.






These birds alternately soar while searching then hover when they see potential prey.   In a short time this kite found a small rodent, made the kill and retired to the top of a piling for its meal.

Later we saw a Northern Harrier hunting in its characteristic style, flying low and slow over the marsh and shrubbery occasionally wheeling to surprise its prey. 

Virtually all sign of life and most structures were wiped off the Bolivar Peninsula, by Hurricane Ike in September 2008.  The 25 mile long spit that separates Galveston Bay from the Gulf, nowhere more than a few feet above sea level, was covered by 20' or more of storm surge.   The winter and spring were unusually dry, with little rain to wash the salt out of soils that had been inundated with seawater.

When we spent a day on a volunteer "clean-up" effort at the Houston Audubon Bolivar Flats Sanctuary in March 2009, there were few signs of life, no insects or small animals and only a few salt tolerant bits of greenery.  It seems that those raptors that hunt rodents and other small animals also were largely absent.

This spring things are different.  The rodents and the raptors that prey on them are definitely back.  The raptors, of course flew here.  I wonder how the "rats" returned.  Had they some how survived in small numbers in the debris?  Had they been stowaways in loads of building materials.  Or, hidden in dumpsters brought in to collect debris?

In any case, the marshes, shores and wildlife are recovering, probably better than the structures of the human community.   The worst damage seems to have been inflicted by the necessity to remove debris, building materials, and millions of plastic bags from the fields and marshes.