NorthernAplomadoFalcon_Chemicals_KeddyHector_Dean_AustinTX_7June2022_Reel4111.mp3

Dean Keddy-Hector [00:00:00] The pesticide load we detected during my first study season was the primary reason for listing the species as endangered. The secondary reasons were the historical declines in the United States. The primary was the risk of pesticide-induced population crashes...

Dean Keddy-Hector [00:00:20] The big concern was that DDT, or its metabolite DDE, messes with calcium metabolism. And, you know, by doing that, the birds lay thin-shelled eggs or, at an extreme, shell-less eggs.

Dean Keddy-Hector [00:00:37] So their productivity drops and, you know, if that process continues enough, then a population that's experiencing that level of pesticide contamination will no longer be sustainable, and will finally decline to extinction.

Dean Keddy-Hector [00:00:52] And the initial work that I was involved in, involved collected egg shells - bat falcons and aplomados - mostly those collected by oologists, the people that used to collect eggs as a hobby in the 1950s and 1960s.

Dean Keddy-Hector [00:01:10] And then the bat falcon levels were just unbelievable. The, their egg shells were incredibly thin. Aplomados, a little bit less so.

Dean Keddy-Hector [00:01:20] But then I contributed egg shell fragments and some addled eggs that we collected in my first field season to make it a little bit more current.

Dean Keddy-Hector [00:01:28] And, but, yeah, there are other concerns about the influence of organochlorine pesticides on behavior, on reproductive behavior. Like when the peregrines were declining in the Northeast due to pesticide contamination, they had observed like the female peregrines eating their eggs, doing kind of aberrant things like that. Or embryo mortality.

Dean Keddy-Hector [00:01:53] But the big concern was the shell-thinning effect, and not much concern in those days about organochlorines as a, as an estrogen mimic. You know, that came along later.

Dean Keddy-Hector [00:02:07] You know, since that time, there have been other, other concerns that have popped up and there are fire retardants that are persistent and biomagnified through ecosystems.

Dean Keddy-Hector [00:02:17] Oh, gosh, the, all the array of these awful second-level rodenticides that are all anti-coagulants, that are persistent, that have been killing so many birds of prey in urban areas and in rural areas and then in secondary contamination.

Dean Keddy-Hector [00:02:32] All of these, all these things that are persistent in the environment, but also very toxic. And any upper trophic level predator's going to be influenced by those sooner or later.

Dean Keddy-Hector [00:02:43] Yeah, my big concern right now are the rodenticides that are so available at Home Depots and feed stores, and have been implicated already. Gosh, I think New York is one area where they've done some amazing, but really discouraging, studies on hawk and owl mortality created by biomagnification of these poisons.