The West Indies 2015-16 CBC season with 21 counts including Bermuda was expanded by a return of the Barbados count, absent for several years. Many thanks to that circle’s compiler for a yeoman’s effort. This count provided a touch of European stragglers and some established insurgents. Cuba has established four counts with the help of visiting observers from North America, a promising arrangement. Puerto Rico continues to provide outstanding results since 1980.
The highest species count belongs to Arecibo, Puerto Rico with 122, followed by Cabo Rojo, Puerto Rico with 118 species. The average number of species for Puerto Rico was 107.25 showing great species richness among several habitats. The Bahamas’ four circles average 89 species. The three US Virgin Islands counts averaged 57.6. The circle with the highest participation was Fajardo, PR with 48 followed by Arecibo, PR (47). Bermuda’s 20 participants reported 93 species.
Some of the most outstanding finds came from Barbados where J Webster found Eurasian Wigeon, Eurasian Marsh-Harrier, Grey Heron, and Little Egrets. Amazingly, another Eurasian Marsh- Harrier was reported from Bermuda as well as a West Indian Whistling-Duck, a long way from its core distribution in the Greater Antilles. Nineteen species of warblers were recorded at Bermuda. In recent years there has been an explosion of Least Grebe reports and this count cycle was a confirmation of that phenomena with 85 reported in the Bahamas and 22 seen in the Virgin Islands (two at St John, 19 at St Croix, and one at Anegada).
Cuba is attracting volunteers to augment a fledgling CBC program. The National Botanic Garden outside of Havana provided many unexpected treats such as the elusive and endangered Gundlach’s Hawk, a charismatic endemic accipiter. An unexpected Mississippi Kite was noted and a striking, rare rufous morph of American Kestrel was also found.
“Dozens of North American birds winter in Latin America, but because we lacked sufficient data to study the effects of global warming on those birds’ winter ranges, it is likely that even more birds are threatened by global warming than we have been able to identify so far.”- Gary M. Langham, Audubon Birds and Climate Report, National Audubon Society. This is a subject that I have been concerned about for some time, particularly since NAS now has a tool to view trends of wintering populations of neotropical migrants as well as resident species. The longer the period of record, the better understanding we can derive from the CBC database. I have provided some results in previous regional analyses.
In this analysis, I chose to look at trends for American Redstart, a fairly common winter resident, at Bermuda, Grand Bahama, and Fajardo, Puerto Rico.
These trends provide mixed evidence of any overall or major climate change effects. At Bermuda, there appears to be a noticeable decline. At New Providence, there may also be a slight decline. Yet for eastern Puerto Rico, American Redstart is either stable or increasing over the last 30 years. Indeed, these results may simply mean there is an observable shift in preferred wintering habitat over this period passed from generation to generation. No doubt there are stressors in breeding habitat, but upward trends in the wintering areas may only mean alternative wintering sites are being exploited.
As a means for a control, graphs of non-competitive, resident species at New Providence and Fajardo not influenced by the same weather phenomena experienced by redstarts during migration, i.e. wind, fronts and precipitation, suggest slight declines as a possible result of localized climate effects, i.e. drought.