I know when I ran the CBC for the Audubon Chapter of Minneapolis we found a huge flock feeding on Buckthorn berries in Island's of Peace Park in Fridley, MN in 2001. It was a flock of over 1000 birds. I think their winter numbers are tied to food, and temperature.
On Thu, Dec 6, 2018 at 6:18 PM JULIAN SELLERS <juliansell...@msn.com> wrote: > I think hackberries play a role. I don't know when the cities began > planting hackberry trees on boulevards, but I think it was not many decades > ago. Most of the trees do not look very old. Did large crops of > hackberries begin to appear within the last 10 or 15 years? > > On the 2008 St. Paul (North) CBC, my team had the area west of Cleveland > Avenue and south of Marshall Avenue/Lake Street, extending south to the > Ford Dam and west past the Hiawatha grain elevators in Minneapolis. We > counted 808 American Robins. As I recall, about 650 of them were feeding > on Hackberries on the Summit Avenue median in the two blocks between Cretin > and Cleveland Avenues. > > It seems to me that robins become scarcer in late December, as the > hackberry supply is depleted. > > Julian > ________________________________ > From: Minnesota Birds <MOU-NET@LISTS.UMN.EDU> on behalf of Rebecca Field < > rebeccafiel...@gmail.com> > Sent: Thursday, December 6, 2018 6:21 PM > To: MOU-NET@LISTS.UMN.EDU > Subject: Re: [mou-net] Northern Raven/Number Winter Robins > > I just heard this evening that Robins eat Buckthorn berries. Of course, we > are trying to eradicate that invasive. I hope that isn’t causing less food > for the robins. > > Becky Field > > Sent from my iPhone > > > On Dec 6, 2018, at 5:36 PM, Jason Frank <jmfran...@gmail.com> wrote: > > > > It would be interesting to compare the data of outstate CBCs as well. > > I haven't lived in Minneapolis during winter since 1997, and it seemed > > noteworthy to me to see large numbers of robins in the winter. A few > > years ago I visited Minnehaha Falls around Christmas and couldn't > > believe how many there were, though I just figured they were local > > birds who stayed for the open water along the creek and had reliable > > food sources nearby. Those numbers from Val show a pretty stark > > increase, which to my eyes fits the trend of climate change. > > > > But... having lived in the Lac qui Parle area since 09, I can't say > > I've seen many impressive winter flocks except during the mildest > > winters of the last decade, and those birds were usually seen in town > > or at parks, and not out in the countryside for the most part. > > > > Since the Twin Cities urban heat island effect means the temperature > > averages there would be trending warmer than elsewhere in the state, I > > wonder if outstate robins have gotten into the habit of migrating into > > cities and towns, rather than further south? Collating banding data > > with rural CBCs might shed some more light on the case. > > > >> On 12/6/18, GREG ELIZABETH CLOSMORE <closmor...@msn.com> wrote: > >> Buckthorn! > >> > >>> On Dec 6, 2018, at 4:32 PM, Val Landwehr > >>> <0000012f44857088-dmarc-requ...@lists.umn.edu> wrote: > >>> > >>> I was intrigued by the discussion of whether in recent years > >>> more robins are being seen during winter in the Twin Cities(Charles > Neil, > >>> Mary White and J. Baumann). I think that I > >>> have seen more robins, particularly in large flocks, in > >>> recent years. To put this hypothesis to the test I looked at the > >>> results from four Christmas Bird Counts over the years that are > >>> online at the Minnesota Ornithologists' Union website. The > >>> Christmas Bird Counts I checked were Bloomington CBC, St. Paul > >>> (North) CBC, Excelsior CBC and the Minneapolis (North) CBC. > >>> I found a distinct trend of more robins being counted during > >>> the counts since the winter of 1996 than were in prior years. > >>> The numbers vary widely each year, but there is a distinct > >>> inflection point around 1996 for a larger number of robinssince that > date > >>> than prior to it. Since 1996, the number ofrobins counted varies > greatly > >>> from year to year, but I don't > >>> see any clear evidence that the numbers are continuing to > >>> increase. > >>> Average number of robins counted at Twin Cities CBCs: > >>> Bloomington St. Paul (North) Minneapolis (North) Excelsior > >>> Pre 21.2 17.1 2.5 > >>> 5.3 > >>> 1996 > >>> 1996- 367.4 420.5 114.6 > >>> 181.2 > >>> 2017 > >>> > >>> Median number of robins counted at Twin Cities CBCs: > >>> Bloomington St. Paul (North) Minneapolis (North) Excelsior > >>> Pre 5 6 0 > >>> 1 > >>> 1996 > >>> 1996- 278 255 26 > >>> 132 > >>> 2017 > >>> I considered that the increased number of robins might reflect > >>> more birders participating in these Christmas counts as well > >>> as an increase in birding skills. If there are more skillful > >>> birders involved in these counts I would expect a similar > >>> increase in the counts of other species. So I looked at the > >>> counts reported by the Bloomington CBC for the black-capped > >>> chickadee, blue jay and dark-eyed junco. I didn't find any > >>> trends or long term changes in the number of these species. > >>> Therefore, I'm convinced that the increased number of winter > >>> robins is real. > >>> I didn't attempt to see if there is a link between the increasein the > >>> number of robins counted and weather/climate. > >>> That leaves a question in my mind. Are the larger counts just > >>> a reflection that the Twin Cities population of robins has > >>> increased but the same proportion of that population is > >>> overwintering as in the past or have the overwintering habits > >>> of the robins changed? > >>> The CBC data speaks only to the presence of robins in December. > >>> Maybe the only change is when the robins migrate to warmer > >>> regions. Maybe if we had many years of counts for January and > >>> early February we would find that the number of robins in > >>> those months hasn't changed much over the years. As Manley > >>> Olson pointed out, once the robins exhaust the availability of > >>> crab apples, perhaps they head south and are now just as > >>> uncommon in January and February as they were back in the > >>> 1950s through 1980s. > >>> Val Landwehr > >>> Minneapolis > >>> > >>> ---- > >>> Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > >>> Archives: http://lists.umn.edu/archives/mou-net.html > >> > >> ---- > >> Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > >> Archives: http://lists.umn.edu/archives/mou-net.html > >> > > > > > > -- > > Jason M. Frank > > Ortonville Public Library > > Founder & Vice President > > Luddite Ornithologists League (LOL) > > Big Stone County, Minnesota > > > > ---- > > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > > Archives: http://lists.umn.edu/archives/mou-net.html > > ---- > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > Archives: http://lists.umn.edu/archives/mou-net.html > > ---- > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > Archives: http://lists.umn.edu/archives/mou-net.html > ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html
