The Boulder CBC once held the annual Christmas Bird Count’s all time highest record for bohemian waxwings in the continental United States, *11,284 individuals seen in one day in 1987! Yes that's 11 thousand! *
On Monday, January 30, 2023 at 6:51:39 AM UTC-7 [email protected] wrote: > I downloaded and compiled all the eBird accepted Bohemian Waxwing > checklists for the Denver Metro area (Denver, Adams, Arapahoe, Douglas, > Jefferson, Broomfield). Hugh Kingery suggested a definition of an irruption > to be greater than 4 birds on a checklist and to cover at least a period of > 2 weeks. I sorted it into date order for these combined 6 counties. After > dropping all checklists with less than 5 birds or an X in the count, I was > left with 215 checklists with BOWAs in the Metro area over a 75 year > period. Hugh had BOWAs back in 1948 close to the zoo. > > eBird was started by Cornell in 2002. Not many birders used it at that > time but it is now widely used. Many birders have entered their historical > records which is such valuable information. Many thanks to all the > reviewers that really make this a trusted source of data. And thanks to all > the birders that are now submitting checklists, we really have a great > resource of birding data. > > David Suddjian was the first to see our current amazing irruption on > 12/23/2022 in Ken Caryl. He confirmed the 20 flyovers by the "tight > formation, size and calls". And it is possible we will continue to see this > current irruption even into April. > > We have to go back *14 years* to get to the closest previous > irruption for the metro area. It was in the winter of 2007-2008. It began > on 12/14/2007 at Chatfield State Park and the last sighting that winter was > at Columbine West on 4/13/2008. The high count that winter was 200 BOWA in > Douglas county on 1/15/2008. > > Going back *2 more years* to the winter of 2004-2005 was a large > irruption year as well. It began on 11/24/2004 in Broomfield and finished > on 3/21/2005 in Douglas county. The high count for this period was 2000 (a > conservative count they said) and was recorded in Adams county at "Federal > & 120th by Norm, Ted, Dave and Marilyn" on 11/30/2004. > > You have to go back another *13 years* to the winter of 1990-1991 to get > another irruption for the Denver Metro area. Beginning on 12/12/1990 at > Chatfield and continuing to 4/5/1991 at Joe Roller's Yates home in Denver. > He had 22 BOWA and commented on their "mean looking facies". There are 5 > records for this irruption winter and the average count was around 40 BOWAs. > > The 1980's had 5 winters with BOWA irruptions. 79-80, 81-82, 84-85, 86-87 > and 87-88. The largest count on a checklist for the 1980's was 1000 BOWA on > 1/12/1988 in Greenwood Village by Hugh Kingery. He made this comment > "Heritage > Village, Littleton (6465 S. Niagara).No details. This month saw a lot of > BOWAs in metro Denver.". > > There is only one year in the 1970's and one year in the 1960's that shows > irruptions in the eBird historical data in the Metro area. 1976-1977 had a > checklist with a high count of 1000 BOWA at Cherry Creek SP on 3/12/1977. > And finally in the winter of 1968-1969 there was a report of 2000 BOWA at > Bow-Mar on 12/20/1968 reported by Van Remsen with this comment "invasion > year; careful estimate". > > As more historical data is entered and as more birders use eBird, the data > will get better. I did download all of the Colorado BOWA data and it > contained right at 1000 records. All of Colorado averages an irruption > every 3 years. But the Denver Metro area, from 1948-2023, has had 11 > irruptions in this 75 year span. So, we average an irruption about every 7 > years. Enjoy this one while it lasts. Sure has been fun. > > Gregg Goodrich > Highlands Ranch > -- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/cobirds?hl=en?hl=en * All posts should be signed with the poster's full name and city. Include bird species and location in the subject line when appropriate * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ --- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/a9d6d457-4a91-4ee5-9e41-b6e141900f4en%40googlegroups.com.
