As fall migration began in early July a flood of shorebirds, songbirds, and hummingbirds started migrating through Colorado. In order to get the most new birds for my Big Year I attempted to find as many rare birds as possible. Not all the birds I needed were rarities, several of them were birds that only migrate through Colorado in the fall.
The first birds to start migrating in the fall each year are hummingbirds. This is a male Calliope Hummingbird, the smallest bird species in North America. They only show up in Colorado during fall migration.Another hummingbird that only appears in Colorado in the fall is the Rufous Hummingbird. This male Rufous was visiting the same feeder as the Calliope.The first rare bird of the fall showed up on the 25th of July. It was a Long-tailed Jaeger at Jackson Lake near Fort Morgan. Jaegers are normally oceangoing birds, so seeing one in Colorado is always a treat. Later in the day at Prewitt Reservoir we saw another migrant, a Black Tern molting into nonbreeding plumage. This was one of a flock of 36 Black Terns we saw that day.Amongst the thousands of shorebirds on the shore of Prewitt Reservoir we picked out a Black-bellied Plover in breeding plumage. The plover was surrounded by the smaller Baird’s Sandpipers and Killdeers.On August 16th we made the drive to Southeastern Colorado to look for a Cave Swallow that had been reported at the west end of John Martin Reservoir. In this picture it is the bird on the right. It was in a large flock of Bank and Cliff Swallows feeding over a distant mudflat. This was only the second record of this species in the state! Later the same day we had another rare bird in the town of Eads. It was an immature male Ruby-throated Hummingbird (on the right) at a private feeder.The first rare shorebird of the fall, a Buff-breasted Sandpiper, was found at Jackson Lake on August 21st. It was reported in the morning and I chased it in the afternoon. After almost three hours of searching without any luck I finally spotted the bird just before sunset!The next rare shorebird, a Ruddy Turnstone, arrived just two days later again at Jackson Lake. I searched for the bird for 3 hours (until it was too dark to see) and was back early the next day hoping it was still around. It only took 45 minutes to find on my return trip, demonstrating the unpredictable nature of birding.On August 28th at Barr Lake I found a Cassin’s Vireo. These birds only migrate through Colorado in the fall. The next bird came one day later along the inlet canal of Prewitt Reservoir. A Black-throated Green-Warbler foraging in a flock of Wilson’s Warblers.One of the most striking warblers of the western mountains, the Townsend’s Warbler. Every year they migrate through Colorado as they go south. This was one of many I saw this fall. I photographed this Townsend’s Warbler on September 5th while looking for a Philadelphia Vireo at Barr Lake.30 minutes after I photographed the Townsend’s Warbler this Philadelphia Vireo popped up and foraged above us in the top of a tree. I had already missed Philadelphia Vireos three times this year so finally getting one was incredible. Storm birding is the best! On September 8th the first blizzard of the winter hit. It caused many migrating birds to land, rest and refuel. One of the rarest birds to show up was a Red Knot at Fossil Creek Reservoir in Fort Collins. It is the grayish blob in the middle of the picture. Because of the heavy snow and fog coming off the reservoir the pictures are less than ideal.A juvenile Sabine’s Gull on the shore of Jackson Lake. These ocean gulls move through Colorado in small numbers every year appearing on large reservoirs.On September 11th a juvenile Common Black Hawk was seen at Manitou Lake eating crayfish below the dam. I watched the bird catch and eat three crayfish while we were there later that day. This was the first Common Black Hawk seen in Colorado since 2015!The next day we got a Little Gull at Chatfield Reservoir with several Sabine’s Gulls. In this picture the Little Gull is the slightly smaller bird on the right with a Sabine’s to the left.The day after that we chased a Yellow-bellied Flycatcher in the town of Eads around the courthouse. I initially identified this flycatcher as the Yellow-bellied, but several months later after consulting other birders it was determined to be the much more common and similar Hammond’s Flycatcher. It’s always painful to lose a bird…While looking for the flycatcher I found a Blue-headed Vireo which paused in a tree for several seconds before flying over the courthouse. We never relocated it. The clean separation between the blue cheek and white throat make this a Blue-headed and not the more common Cassin’s Vireo.
