Andy and all, the below link may assist in understanding. Issues from their main central Mexican wintering roosts, from much of their migratory passage habitat and - [possibly even more than the latter two factors] - that which is discussed in the link can be factored in to a decline of the N. American population of Monarch butterflies and the phenomenon of their great migrations.
http://e360.yale.edu/feature/tracking_the_causes_of_sharp__decline_of_the_monarch_butterfly/2634/ Just by chance I had a brief correspondence with a hawk-watch counter at Detroit where a slightly more hopeful number of Monarchs were seen on this day, all headed south from there - said to have been upwards of 75-100. We hope there may yet be more as it may remain at least mild enough for late emergence of migratory-brood adults thru some of the U.S. and for now perhaps even in s. Canada. Good everything-watching, Tom Fiore, Manhattan ---------------------- On Oct 8, 2013, at 10:01 PM, <andya...@aol.com> wrote: > I have heard comments on the decline of quantities Monarch > Butterflies this fall. I have also found a great decrease in the > migration in the east > on Long Island. The fall monarch nature trips also have found very > few. > > I would appreciate it, if someone who is knowledgeable about this > would care to comment. I have heard all kinds of speculations from > birders, but no comments from those who study this, and are > knowledgeable about the reason and have statistics showing how much > this Monarch Butterfly migration is much lower than previous years. > In fact I think the migration has been lower every recent year, but > this year is the worst. > > Thanks for your input, I realize this is not birding, but I think it > is of interest to birders. > > Andy Murphy -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
