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
