Dave, et al, By the 1970s, there could have been a noticeable change in bird populations due to the banning of DDT in the 1960s. Interesting conversation... Steve Taylor Pittsford NY
Sent from my iPhone > On Jun 26, 2019, at 8:02 AM, David Nicosia <daven102...@gmail.com> wrote: > > John/Chris, > > I totally agree that point counts from birding could misrepresent bird > populations. I have been out on two different days and have seen big > differences. I have a walk I take in the evening to listen to the thrushes. > One evening I had 5 wood thrushes and 1 hermit thrush singing. The next night > I had 3 hermit thrushes and 1 wood thrush. If you were doing a survey your > numbers would depend on which night you chose. In Broome Co we don't have as > much farming as John does and his comments on the large scale agriculture and > the destruction of habitat on farms would make a big difference locally. > Anyway, what do you make of this banding dataset from Canada? > https://www.bsc-eoc.org/birdmon/default/popindices.jsp > > I look at Long Point Bird Observatory since it seems to have the longest > record. It seems that most species are doing very well on this long term > dataset. It is interesting to note an increase in the 1970s for most species. > Is this artificial? or real? I know the climate of the 60s and 70s was very > chilly and springs were often cold and wet then it warmed in the 80s and 90s > especially. But I don't understand how they calculate their population index. > I assume it is normalized to the man-hours of banding. But what happening in > the 1970s? Why such increases? From 2006-2016 most birds seems fairly stable > based on their population index. > > Anyway, what are your thoughts on this? I am curious. > > Also there was a study on breeding bird survey data and they found that some > of the data is contaminated by observers who, through normal aging, lose > hearing. This was especially true of certain species that have higher pitch > songs. So BBS may not be totally reliable either. > > Is anyone doing a study on total radar returns during migration? > Theoretically, spring and fall migration could be quantified by integrating > all the radar returns at night. I know there was a study done many years ago > which used the old NWS radar system and compared the 1960s to the 1990s and > they found a significant decrease in birds coming across the Gulf. But, I > caution that radar operators could adjust the gain on the radar from site to > site which would in turn, affect the returns so there could be some human > caused inconsistencies in this dataset. Plus the 1974C radars came out which > were less sensitive than the 1957S band radars. I wonder if this caused the > decrease or contaminated the data for this study. Our latest radar system > from the 1990s to present, you can't adjust the gain and they are all the > same wavelength - 10 cm, so it is consistent. The resolution has gotten much > better in the last 15 years so that could be a source of error if one looked > at the 1990s and compared it to today. But at least over the last 10-15 years > I believe one could quantify all radar returns which would give a macroscale > look at nocturnal migration and monitor trends. Boy would I love to have time > to do this!! I have 6 years to go until retirement.... Maybe someday I can > work on this... > > Anyway, just some thoughts. Thanks John and Chris for your insights! > > Best, > Dave > > > > > > > > > >> On Tue, Jun 25, 2019 at 8:43 AM <k...@empacc.net> wrote: >> Dave, Chris >> >> I believe one has to look further than two years and at efforts that use the >> same methodology and criteria over long time periods for an accurate >> estimate. The American Bird Conservancy and the Bird Banding Laboratory are >> perhaps the best sources as are some of the long term banding studies >> documented in journals such as North American Bird Bander. >> >> Regardless of cause it is to be expected that there will be some pockets of >> plenty. >> >> The causes I believe are multiple, cumulative and you mention some. Habitat >> loss and obstructions have increased dramatically and quickly in the last >> two decades. Locally a very large negative is the growing dairy >> agribusinesses that are converting pasture and hedgerows to large swaths of >> sterile, monocropped land. Beyond this area chickens and hogs are being >> raised with the same methods and habitat loss. South and Central America >> habitat loss has also been on the rise. >> >> Yes a few species have been documented to have cyclical ups and downs. A few >> may also be subject to WNV and I believe Anne would have better data on that >> than I. >> >> Any counts that are aperiodic could well be the result of the cyclic nature >> of weather, blocking fronts, timing during migrations, observer bias and >> more. >> >> Insect populations are indeed crashing and the 'Have you see any bugs on >> your windshield?" type articles have increased awareness, but the loss has >> not been adequately studied. The combination of all this has greatly >> decreased habitat and food sources at the lower end of the life web. >> >> In any event I do not believe we can rely on birder reports for meaningful >> data but should rather look to long term studies with timing and protocols >> that are standard year to year. >> >> Thanks for your input. >> John >> >> --- >> John and Sue Gregoire >> Field Ornithologists >> Kestrel Haven Migration Observatory >> 5373 Fitzgerald Rd >> Burdett, NY 14818 >> 42.443508000, -76.758202000 >> "Create and Conserve Habitat" >> >>> On 2019-06-23 20:13, David Nicosia wrote: >>> >>> Chris, >>> >>> Fortunately, I have found the opposite for the most part.... >>> >>> I did two trips this past week one to Triangle State Forest and Hawkins >>> Pond State Forest in Broome County and neotropical migrants were quite >>> common especially Red-Eyed Vireos, Ovenbirds. >>> >>> see: Triangle State Forest: https://ebird.org/view/checklist/S57456491 >>> Most of the warblers were found in a small stretch of about 1 mile in the >>> spruce, hemlock, pine, northern hardwood forests. >>> >>> and Hawkins Pond State Forest: https://ebird.org/view/checklist/S57564971 >>> Most of the birds were in the stretch of spruce, hemlock, pine and maple, >>> oak about 1.5 miles. >>> >>> I lost count of ovenbirds at Hawkins! Red-eyed vireos were all over. >>> Blackburnian warblers too were the most I have had at this location. Now >>> this is just my observations in one county. >>> >>> In the western Adirondacks, at Star Lake, Red-Eyed Vireos seemed everywhere >>> along with ovenbirds. Blackburnian warblers were quite common too. >>> >>> see: https://ebird.org/view/checklist/S57189909 for my Star lake walk. >>> >>> In my yard, there also seems to be more bird activity this year. I have at >>> least 2 maybe 3 pairs of Gray Catbirds this year vs just one pair most >>> years. I also have 2 pairs of red-eyed vireos vs one pair or in some years >>> none! >>> >>> Anyway, what is the cause of the drastic declines that you are observing? >>> That is the bigger question. Could it be disease? Does west nile virus >>> kill songbirds? Have insect populations crashed? Habitat loss, increase >>> in towers, wind farms etc are happening gradually so the declines should be >>> slow. Or maybe there is a natural cycle and some areas are seeing the >>> minimum in numbers which is lower than any other minimum in the past? >>> >>> Concerned too (but optimistic), >>> Dave >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>>> On Sat, Jun 22, 2019 at 9:01 PM Christopher T. Tessaglia-Hymes >>>> <c...@cornell.edu> wrote: >>>> Good evening, >>>> >>>> This morning I was joined by Bartels Science Illustrator, Jessica French, >>>> for a birding trip to Hammond Hill State Forest. It was disconcertingly >>>> quiet up there. I probably should not have had such high expectations, >>>> given how quiet this spring has been (a handful of very quiet trips to the >>>> Hawthorn Orchard) and how few night flight calls were recorded over our >>>> house in Etna. I'm still analyzing my night flight call data, but those >>>> data from May 3 through May 24 are concerning, to say the least. I have >>>> also read postings from VINS and notable Bicknell's Thrush researcher, >>>> Chris Rimmer, making similar observations about his Mount Mansfield, VT, >>>> field site this spring ("disquietingly low" vocal activity and mist net >>>> captures). >>>> >>>> Here are two checklists completed from our two, approximate four-mile, >>>> bushwhack walks this morning. Nice habitat. Few insects. Few birds. No >>>> ticks (but not complaining). >>>> >>>> Loop to SE of Star Stanton and Canaan Rd Intersection: >>>> >>>> https://ebird.org/view/checklist/S57605395 >>>> >>>> Notably absent or low numbers of birds -- >>>> Barred Owl >>>> Red-bellied Woodpecker >>>> Pileated Woodpecker >>>> Least Flycatcher >>>> Great Crested Flycatcher >>>> Red-eyed Vireo (very low numbers) >>>> Winter Wren >>>> Wood Thrush >>>> Baltimore Oriole >>>> Mourning Warbler >>>> Hooded Warbler >>>> American Redstart >>>> Chestnut-sided Warbler >>>> Black-throated Blue Warbler >>>> Black-throated Green Warbler >>>> Canada Warbler >>>> Scarlet Tanager (very low numbers) >>>> Rose-breasted Grosbeak >>>> >>>> Loop between Hammond Hill and Canaan Rd: >>>> >>>> https://ebird.org/view/checklist/S57605776 >>>> >>>> Notably absent or low numbers of birds -- >>>> Barred Owl >>>> Red-bellied Woodpecker >>>> Pileated Woodpecker >>>> Least Flycatcher >>>> Great Crested Flycatcher >>>> Red-eyed Vireo (very low numbers) >>>> Winter Wren >>>> Wood Thrush >>>> Baltimore Oriole >>>> Mourning Warbler >>>> Hooded Warbler >>>> American Redstart >>>> Chestnut-sided Warbler >>>> Black-throated Blue Warbler >>>> Black-throated Green Warbler >>>> Canada Warbler >>>> Scarlet Tanager (very low numbers) >>>> Rose-breasted Grosbeak >>>> >>>> Concerned, >>>> Chris T-H >>>> >>>> -- >>>> Chris Tessaglia-Hymes >>>> PO Box 488 >>>> 8 Etna Lane >>>> Etna, NY 13062 >>>> 607-351-5740 >>>> -- >>>> 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! >>>> -- >>> >>> -- >>> Cayugabirds-L List Info: >>> Welcome and Basics >>> Rules and Information >>> Subscribe, Configuration and Leave >>> Archives: >>> The Mail Archive >>> Surfbirds >>> BirdingOnThe.Net >>> Please submit your observations to eBird! >>> -- > > -- > Cayugabirds-L List Info: > Welcome and Basics > Rules and Information > Subscribe, Configuration and Leave > Archives: > The Mail Archive > Surfbirds > BirdingOnThe.Net > Please submit your observations to eBird! > -- -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
