Migration is complex in the LCRV. Spring migration begins in January, when swallows and some waterfowl begin to move north. The latest of spring migrants are here in June, which is also when fall shorebird migration begins. November marks the arrival of many wintering duck species. At practically any time of year, something is migrating in the LCRV.
The appearance of spring migrants in late winter is probably related to the mild climate and abundant food resources of the region. Also, some of these movements may not pertain to migration as much as shifts in the wintering range. According to Rosenberg et al. (Birds of the Lower Colorado River Valley, 1991),
“…there is evidence that some species may make midseason adjustments in their winter quarters in response to sudden changes in local weather or food supply. These moves may be in the form of continued migratory behavior, as in some small insectivores, or as massive invasions into more suitable habitat, as in berry-eating waxwings and thrushes. …Thus, the notion of a static winter range for many species may be inappropriate, as winter in the lower Colorado River Valley is very much a time of flux.”
Below, I’ve recorded some of the early movements that we have seen in January and February. (This only includes a few observations from other birders.) Our field observations are compared with Rosenberg et al., the standard reference for the region.
The first report of this species in the region this year was by John West, who counted nine in the Castle Rock area on January 2. David and I had two at Pintail Slough January 24, and Kathleen Blair had two on the Bill Williams January 25. Our first flock of the season was at Pintail Slough February 20, when we had ten. By February 26, the number at Pintail Slough increased to about 80. It is not unusual for a few individuals to arrive in early to mid-January, with migration picking up in early February. It seems that Cinnamon Teal migration is happening a few weeks later than “typical”.
Our first and only Blue-winged Teal this season was a drake in Lake Havasu City January 27. This species occurs irregularly in the LCRV, though spring migration typically begins in mid-February.
David’s FOS Red-breasted Merganser was off Take-Off Point on February 4. Sightings of one on Lake Mohave February 20 and two on Lake Havasu February 22 were more typical of early migrants, which usually appear around mid-February.
This winter had Turkey Vultures wintering further north and migrating earlier than listed in Rosenberg et al. While this species was formerly absent in winter north of Parker, we had about 11 wintering in the Parker Strip, as well as one individual in the Mohave Valley seen January 5. We observed migration beginning in mid-January, when scattered individuals arrived around Lake Havasu City. The first flock we saw north of Parker Dam was of 19 birds near Catfish Paradise on February 22. Other flocks have been observed since that date. This is slightly earlier than noted in the book, when spring migration began in early March.
This species is an uncommon winter resident. Our first migrant of the season, a singing bird at Pintail Slough February 20, was right on time.
We observed the largest concentrations of wintering birds on Lake Havasu, especially the north end. Estimates of larger flocks during the winter ranged from 200-400. We observed the first influx on February 18, with 770 at the north end. Flock sizes then began to increase throughout the region, and our high count in February was 1200 at the north end of Lake Havasu February 26. Distribution of this species is complex and highly variable year-to-year, though peak spring migration occurs in March.
Migration of this species began as a trickle this year. The first report of the season was January 19, when Kathleen Blair recorded five at Kohen Ranch. My FOS was one in Lake Havasu City February 1; I saw another on the Parker Strip February 3. We didn’t see more until February 20, with two at Pintail Slough and one on Lake Mohave. Since February 21, numbers have greatly increased, with a few counts of 10 to 30 birds and widespread scattered individuals. This seems to be a slightly late arrival of this species; migration typically begins in early February.
Northern Rough-winged Swallow
Numbers of this species seem to be low this year. Small numbers wintered south of Parker Dam. Beginning in late January (as is typical), we began to see small numbers as far north as Willow Beach. Our high count is 15, from Pintail Slough February 26.
Arrival of Cliff Swallows this year seems typical. The first reported in the region was on February 22, when Kathleen Blair had one at the Bill Williams NWR HQ. David and I had our FOS two days later in Lake Havasu City.