Period 9 in MAPS marked the beginning of the rush of juveniles and the end of vocal adults.
At Rodeo Grounds we caught our first juvenile Least Flycatchers, a couple of juvenile Swainson’s Thrushes and a juvenile Gray Catbird. The difference in the color of the eyes between adult and juvenile catbirds is striking! The Robins have stopped singing at the site, but for some reason we have tons of vocal Swainson’s. We hadn’t heard them at Rodeo until today, let alone caught any. A good start to period nine, with few recaps but many, many juvenile birds including: House Wrens, Leasts, Gray Catbirds, Swainson’s, Redstarts and Song Sparrows.
At Old Baldy the Yellow Warblers, White-crowned, Black Headed Grosbeaks, Black capped chickadees, Veerys, Clay-colored Sparrows, Pewees and Leasts were still singing, but we didn’t hear Robins, House Wrens, Song sparrows or Common Yellowthroats. We caught a lot of juvenile Cedar Waxwings and a very interesting thing was happening; adult Cedar Waxwings AND American Robins were getting very upset. The Cedar waxwings would start making alarm noises and within ten seconds there would be no less than five Robins perched above the net screaming.
At Spruce Coulee just over half the birds caught were juveniles. The new juveniles were Yellow Warblers, a Ruby Crowned Kinglet and a Dusky. Like the Robins at Old Baldy who got upset over juvenile Cedars in the net, we had families of chickadees getting upset when juvenile Sapsuckers were caught. It got much quieter at Spruce Coulee. Originally it was by far the most vocal site, now the only birds we heard consistently were Veerys, Pewees, Least Flycatchers and House Wrens.
Period 10 in MAPS was a Juvenile- Superperiod without a doubt.
By period 10 the sites were becoming very quiet, fall is approaching. The grasses at Rodeo grounds were over our heads, the mosquitoes finally dwindled in numbers, the dragon flies were around by the thousands and fewer and fewer birds were heard singing. At Old Baldy there were still tons of Saskatoon berries and almost all the birds we caught had berry-stained beaks. The meadow at Spruce Coulee had been essentially taken over by Bull Thistle and roses – but there were still some Saskatoon berries, lots of hawthorn berries and some raspberries. The mornings (before 9am) were incredibly busy; we generally caught ¾ of our birds in the first four net runs. We caught mostly juveniles in Period 10; always significantly more than half the birds caught were hatch year birds. We started seeing some crossbills fly through, but it seemed that the migration had not yet begun. It is important in MAPS that migrating birds not be caught, that’s why the study has been carefully placed in the peak of summer during breeding. If migrating birds are caught it skews the population estimates for the area.
So the MAPS project has ended at Cypress Hills Interprovincial Park and the Fall Migration Monitoring begins at the same station we were banding at in the spring.