Hi Gus and all, The curve in the link has the shape characteristic of exponential decline at a constant rate. It has the properties you describe, with the amount of absolute loss diminishing in the recent years, because the population itself is getting smaller all the time. I suspect that this graphic is not to be taken literally but instead is a simple, fitted function meant to express the overall rate of loss that was estimated over these decades.
Best, Shai ________________________________________ From: bounce-123944861-3714...@list.cornell.edu [bounce-123944861-3714...@list.cornell.edu] on behalf of Gus Keri [gusk...@zoho.com] Sent: Saturday, September 21, 2019 6:57 PM To: Anne Swaim Cc: NYSBIRDS-L-for posts posts; Birding alert, ebirdsNYC, Birding alert Subject: Re: [nysbirds-l] Fwd: News Alert: North America has lost 29% of its birds since 1970, study finds. Experts blame habitat loss, pesticides, light pollution and cats. https://www.allaboutbirds.org/vanishing-1-in-4-birds-gone/ The shape of the curve on the graphic in the above article is very intriguing to me. It starts with a steep decline in the first couple of decades and plateaued toward the last few years. The curve suggests that more than 75% of birds losses happened in the first 25 years (betwween 1970 and 1995) and less than 25% of the losses took place in the last 25 years(from 1995 to present). The fact that habitat loss, climate changes and other adverse environmental changes are worse in the last 25 years compared to the previous period suggests other factors are at play to slow down the decline of the total population. Does anyone have any explanation for this contradiction? Sent using Zoho Mail ---- On Fri, 20 Sep 2019 07:18:43 -0400 Anne Swaim <annesw...@gmail.com> wrote ---- > The unformatted PDF version of the study is now openly linked on Cornell > Lab's website > here:https://www.birds.cornell.edu/home/wp-content/uploads/2019/09/DECLINE-OF-NORTH-AMERICAN-AVIFAUNA-SCIENCE-2019.pdfand > also linked from accompanying Living Birds article > here:https://www.allaboutbirds.org/vanishing-1-in-4-birds-gone/ > > Anne SwaimSaw Mill River Audubonwww.sawmillriveraudubon.org > > > > On Thu, Sep 19, 2019 at 9:29 PM Anne Swaim <annesw...@gmail.com> wrote: > Further on this topic: someone just passed along a PDF of full text of the > study. > Reply off list, if a copy would be of interest. > Anne SwaimSaw Mill River Audubonwww.sawmillriveraudubon.org > > > -- NYSbirds-L List > Info: Welcome and Basics > Rules and Information > Subscribe, Configuration and Leave > Archives: The Mail Archive > Surfbirds > ABA Please submit your observations to > eBird! -- -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME.htm http://www.NortheastBirding.com/NYSbirdsRULES.htm 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://birding.aba.org/maillist/NY01 Please submit your observations to eBird: http://ebird.org/content/ebird/ -- -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME.htm http://www.NortheastBirding.com/NYSbirdsRULES.htm 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://birding.aba.org/maillist/NY01 Please submit your observations to eBird: http://ebird.org/content/ebird/ --
