To say I had a busy spring would be an impressive understatement! I continued my part-time job with the City of Lake Havasu, but caved to my desire to get out in the field by working for the Great Basin Bird Observatory. The GBBO is doing work for the U.S. Bureau of Reclamation, which is doing a lot of work creating and monitoring habitat on the LCRV. The main part of this work that I’ve been involved in is the Multi-Species Conservation Plan (MSCP), through which the Bureau monitors certain focal species that are not federally listed. Those that are listed or candidates – Yuma Clapper Rail, Yellow-billed Cuckoo, Southwestern Willow Flycatcher – are covered by species-specific projects. The Bureau has done a lot of great work with the MSCP and gathered an impressive amount of data. The technical reports are available online here, a very interesting resource.
The project I helped with this spring was aimed at quantifying the use of different riparian habitats by breeding birds, especially MSCP covered species – Gilded Flicker, Gila Woodpecker, Yellow Warbler, Bell’s Vireo, Summer Tanager, and Vermilion Flycatcher. Essentially, we were surveying 400m x 400m (ish) plots, recording migrants and mapping every breeding bird we could locate in a morning. The plots were randomly selected, falling from Laughlin to Yuma, and up the Bill Williams River almost to Alamo Dam. I won’t go over the protocols and study design in detail here – you can read about it in the 2009 report.
Since I was also working for the city, I was working a bit less than the others on the project, but I was still plenty busy. I surveyed one site twice a week, another site once a week, and several sites only twice over the season. The twice a week site was my “extreme intensive” at ‘Ahakhav Tribal Preserve. I was pleased as punch to visit that site 16 times over the field season! Since it’s a habitat creation site, it’s easy to walk around and find nests, and it is also full of birds. The Vermilion Flycatchers and Lawrence’s Goldfinches breeding there were especially fun to watch. The site I visited once a week was actually immediately adjacent to the hill we scan the north end of Lake Havasu from, which we call “Lehman Hill”. The hill is the southern boundary of the plot, which extends north about a kilometer in a dense tamarisk/mesquite stringer with patches of arrowweed and some big willows. The breeders weren’t as interesting, but the site was great for migrants. Since the site ran along the shore of the lake, I surveyed it by kayak several times.
|Ahakhav, great spot to spend two days a week|
|Vermilion Flycatcher babies!|
|Kayaking the north end|
My other surveys were mainly in La Paz County. Several were in Cibola NWR, one was in Mosquito Flats on the Bill Will, and one was up the Bill Will at Lincoln Ranch, about six miles downstream from the Alamo Dam. One fell in San Bernardino County near Needles, and I also surveyed the Island STP in Lake Havasu City.
|Lincoln Ranch Rd|
Just for fun, I put together this summary of spring migration on the LCRV. This only includes regular migrants, not rarities. I also omitted any species for which I didn’t get a good sense of their migratory patterns – for example, I missed the arrival of Lucy’s Warblers and saw my FOS long after many had arrived. This only includes my sightings, so it is by no means a complete summary of migrants this spring. To read about rarities and overall sightings, we’ll have to wait for AZFO’s spring Seasonal Report.
This being a 12-page word document, I thought I’d stick it behind a cut…
Numbers fell gradually from early to late March, with the exception of a count of 40 at Beal Lake April 9. Most migrants seemed to be gone by mid-April. Females at Hart Mine Marsh and New South Dike April 30 and May 15 (respectively) may be summering.
Wintering birds and/or migrants remained in the area through March, including a count of 120 in Lake Havasu City March 4. At another site in LHC, numbers dropped from 39 on March 30 to 6 on April 18. My last observation was a flock of 8 at Hart Mine Marsh, Cibola NWR on April 30.
Migration dropped off in March, although I did count 37 at Pintail Slough on March 26. Small numbers continued through April and the first week of May. Three continued at Pintail Slough May 22, possibly summering.
Migrants dropped off suddenly in early April. My latest observation was of 20 at Beal Lake April 9.
Migrants trickled through this spring, with two still in Lake Havasu City April 15.
Forty-eight remained at Pintail Slough by March 26. Four at the same location May 22 were quite late.
Small numbers remained through early April. My latest observation was one at the north end of Lake Havasu April 8.
While numbers dropped off in February, small numbers remained through mid-April. My latest observation was of two in LHC on April 15.
Nothing about this species was typical this winter, so a count of 108 in the BWD March 10 was little surprise. By March 24, numbers at the same location had dropped to 31. One was still at the north end of Lake Havasu May 4.
Wintering flocks were gone by the end of February. My latest migrants were a flock of 12 off Rotary Park on April 9.
Numbers at the north end of Lake Havasu dropped off gradually through March then sharply in early April. A count of 40 on April 2 was reduced to 10 on April 8. About the same number remained throughout April, and six remained by May 11.
Flock sizes at the BWD decreased around mid-February, though good-size flocks remained through mid-March. For example, 41 were counted there March 10. My latest were two at Mesquite Bay April 5.
According to Rosenberg et al., this species should be gone by April. A male at the north end of Lake Havasu April 2 wasn’t exceptionally late, but a female at Rotary Park April 13-14 was more surprising.
My latest observation was of a flock of nine flying over Rotary Park March 18.
Migration began in late February and continued through the beginning of April. My highest count was at the end of this period, with 120 at the north end of Lake Havasu April 8. A flock of six at the same location April 26 was far behind the rest, though Rosenberg et al. note migration continuing into May.
Rosenberg et al. show wintering birds remaining until mid-May, with only a few remaining through the summer. The pattern we have seen this spring has been quite different. A noticeable migration peak occurred at the north end of Lake Havasu throughout February, and 130 were present there March 3. Numbers fell to 50 there on April 2 and to two only six days later. The following single individuals were noted in June: BWD June 5, north end of L. Havasu June 8, and Hart Mine Marsh June 11.
Numbers seemed to match their status in Rosenberg et al. They list it as common through the end of April, with stragglers through mid-May. At the north end of L. Havasu, our counts included 10 April 9, one April 20, nine April 26, and a single bird thereafter through May 11.
While this species was unusually numerous this winter and spring, departure time was typical (early April). Eight on Lake Havasu March 11 was a good count, and my latest was one at the north end of Lake Havasu April 9.
Migration of this species was impressive this April. Some of my counts on Lake Havasu were: 12 April 2, 310 April 8, 500 April 13, 800 April 14, 130 April 26, 80 May 3, and 40 May 9. A few are summering at the north end of Lake Havasu.
Wintering individuals departed in mid-February. My only spring observations were of one or two birds at the Island STP in LHC 11 and 30 March.
No real migration was observed of this species, only a flock of 160 coming in from the east to the north end of Lake Havasu April 26.
Apart from several wintering birds, migration timing matched Rosenberg et al. well. My first migrant was in LHC March 11, and my latest was over the north end of Lake Havasu May 11.
Rare in May, so one in the Parker Valley May 1 was on the late side.
My latest of spring were two at ‘Ahakhav April 25, though I know others had later dates.
My earliest was over Havasu NWR April 4. I repeatedly saw an adult cruising over ‘Ahakhav through May 27, an extremely late date, but other observers continue to see this individual, apparently summering in the area.
One at the Island STP in Lake Havasu City April 28 was late.
Since their status is somewhat unique in the area, regular in every month except April, it’s worth noting my three spring observations: one over the Island STP in LHC April 14, one over Rotary Park May 12, and one over the north end of Lake Havasu May 18.
My latest was at New South Dike May 15.
Only one individual was detected to my knowledge, a long-staying bird in alternate plumage at the Island STP in LHC. My dates for it are April 14 and 15, though others had it before and after.
Passed through in very sparse numbers this spring (that I saw, at least!). I only observed this species twice, both times at the north end of Lake Havasu: on March 30, three birds; on March 31, two birds.
Though this species is only a rare spring migrant, one at the Island STP in LHC April 28-May 3 was on time.
Spring migration seemed to happen in a rush, and it occurred from late April to early May rather than in late March to mid-April, as is typical. My observations were (wintering birds aside): one at Rotary Park April 26, one at the Island STP April 28, and another or the same bird there May 3.
Migration was bizarre for this species this year. It should be common from early April to mid-May. I only observed two, one at Hart Mine Marsh April 30, and one at Rotary Park May 23.
My only observation was one at the Island STP May 3.
A flock of 35 was seen flying north over the north end of Lake Havasu March 30.
One at the north end of Lake Havasu March 31 was my FOS, followed April 9 by an impressive flock of 83 at Rotary Park. Another was at Rotary Park May 3.
My FOS was a flock of 8 at the Island STP April 14. Small numbers were seen around LHC until April 28, when I had two at the Island STP. Hart Mine Marsh had much more impressive numbers, with as many as 70 (April 30)
Small numbers wintered, but my first count over 10 this spring was at the Island STP April 14, with 15 birds. My high count was 30 at Hart Mine Marsh April 24, and my last of the season was 7 at the Island STP May 3.
This species winters in good numbers, so it’s difficult to discern the beginning of spring migration. My last observation was of 2 at the Island STP May 3.
My latest this spring was one at the Island STP April 28.
I was surprised not to see this species regularly this spring. In fact, the only ones I saw were in a flock of 9 at the Island STP May 3.
This species proved just as scarce this spring, with one flock of 4 at the north end of Lake Havasu May 9.
Migration of this species was impressive this year. I suspect that large numbers typically pass through undetected through a narrow range of dates, and we happened to see some of these birds this year. March 30, we counted 45 at the north end of Lake Havasu and 44 at Rotary Park. The next day, only 10 birds were at the north end. Three were at the north end May 9.
One at the north end of Lake Havasu April 26 was exciting, but I was surprised to count 27 at Rotary Park May 3.
Numbers seemed to drop gradually through February into early March. Numbers were greatly reduced after that, though flocks remained at Rotary Park through the first week of May. My latest sighting this spring involved 4 at Rotary Park May 17.
With no real gaps in sightings this year, it seems that spring and fall migration overlapped for this species. Notable counts were ten at the north end of Lake Havasu March 30, followed by 23 there the next day.
Since this species disappeared very suddenly in early February, one at the north end of Lake Havasu April 26 was a surprise.
This is another species with an early fall migration, though there is a noticeable gap in sightings in May. My first sighting was on the Colorado R. adjacent to Havasu NWR March 26, latest was one May 4 at the north end of Lake Havasu. My high count for the spring was only 3 (April 8), in contrast with higher numbers that have been coming through during their fall migration.
I was always pleased to see this scarce migrant. My sightings were four at the north end of Lake Havasu May 9, two there May 18, and one in the BWD May 20.
I’m a bit puzzled by a handful of sightings we had in January, since I didn’t see this species again until April 13, when one turned up at Rotary Park. Two flying over the Colorado R. adjacent to Cibola NWR April 30 were my last of the spring. At the north end of Lake Havasu April 29, I saw an astounding flock of 60 flying over!
I previously mentioned our first of the spring in late February. Numbers increased rapidly from early to mid-April, until this species became one of the most abundant birds throughout the LCRV.
I believe that my FOS in LHC March 15 was likely indicative of an early arrival. However, I didn’t see another until April 16, probably because I wasn’t out at good times for seeing crepuscular birds until that date.
I was surprised by the abundance of this species in the LCRV this spring. The first date I observed them, April 26, I saw 10 at the n. end of Lake Havasu, 3 at Rotary Park, and 2 at the north end again that evening. The peak of migration I observed was an amazing flock of 30 at Rotary Park May 9 (also that day I saw 6 at the north end and 5 at Ahakhav). My latest for the season was May 18, with four at the north end.
After picking up my FOS on Havasu NWR March 26, I began to see this species regularly. Of course, they only increased in abundance and proved to be a very common and widespread breeder in the valley.
It is very difficult to track migration patterns for this species, but I did notice a great deal of movement this spring. Numbers seemed to drop sharply in mid-May. On May 13 at Ahakhav, I counted 14 individuals. My next visit to Ahakhav May 21, I only had four!
I noted this species consistently through April 17. After that date, my only observation has been of one on the Bill Williams May 14.
This species seems to be mostly gone by the end of February. My latest observations were one at Pintail Slough Feb 20, at Parker Oasis April 10, and the Bill Williams April 11.
Red-shafted Flickers lingered in the Valley through March 12, when I had one at ‘Ahakhav.
This proved to be a scarce migrant, with my observations, all of a single bird at ‘Ahakhav, on May 21, June 1, and June 3.
My FOS were three at ‘Ahakhav April 25, continuing in the Valley through June 11, with one at Hart Mine Marsh. The peak of migration this year seemed to occur the first few days of June; my high count was 15 at ‘Ahakhav June 1.
My FOS was at ‘Ahakhav May 9. Considering the status of Southwestern Willow Flycatcher as a scarce breeder in the LCRV, it is a bit complicated to figure out the latest spring migrants. As near as I can figure it, my latest spring migrant was in the Parker Valley June 5. Even as migrants, this species is certainly uncommon; I had no counts greater than 5.
I was a bit surprised by the scarcity of this species this spring, despite its status as the second most common migrant Empid in the LCRV. My first and last of season (both at ‘Ahakhav) were, respectively, April 16 and May 23 (3 birds). I twice had a high count of 5 at ‘Ahakhav, April 25 and May 9, although I generally did note a few Dusky/Hammond’s.
I believe this species was more common this past winter in the LCRV than it was as a spring migrant! The wintering individual at ‘Ahakhav lingered through April 10. My only migrants were at Rotary Park April 28 and New South Dike May 15.
I didn’t realize until May that this species would be so rare in the LCRV during migration. Although I have a number of Dusky/Hammond’s in my notes, the only bird I actually identified as a Dusky was on the Bill Williams May 14.
Witnessing the migration patterns of this species was one of the most satisfying experiences of my spring. Since I am using eBird to write this document, and I tended to enter calling females as “Western” Flycatchers, my notes exclude a good deal of birds seen. Still, the patterns are interesting. My first was at the Bermuda Restoration Area March 16. I didn’t see another until April 16, my first survey at ‘Ahakhav. My last of the season were at ‘Ahakhav, two on June 10. The peak of migration was May 9, an Empid-filled survey at ‘Ahakhav during which I counted 34 Empids: 1 Willow, 5 Hammond’s, 3 Dusky/Hammond’s, and 25 Pacific-slope/Western.
My earliest spring arrivals were two at Lincoln Ranch on the Bill Williams – granted, not in the LCRV, but close enough. I was thoroughly confused by this species throughout the season, as they seemed to pair up and establish territories only to disappear completely on my next visit.
For some reason, I found this species oddly elusive at the beginning of the spring. While others were observing them earlier, I finally saw my FOS – 11 birds in the Parker Valley – April 10.
During the spring season, I did not realize the scarcity of this species in the LCRV, so I wasn’t looking critically enough at birds that appeared to be Plumbeous Vireos. The one I am sure of was a singing male at ‘Ahakhav March 12, but I have changed my other observations to Plumbeous/Cassin’s. In the future, I’ll know better! This is a good example, I think, of holding accuracy above precision, and not considering the species level the final word in identification.
My earliest was April 9 at Rotary Park. This was an uncommon migrant; I counted three several times, but my high count was only 5 at ‘Ahakhav May 23. My only observation after that date was of one at ‘Ahakhav June 3.
My first recorded was at Parker Oasis April 10. Migration peaked early, with 10 at CVCA April 23, but I recorded migrants through June 10 (‘Ahakhav).
My high count during spring migration was 7500 birds, a veritable swarm over the north end of Lake Havasu April 2. Numbers dropped off sharply and this species was uncommon by May. My later observations are: two at the north end of Lake Havasu May 25, one on Cibola Lake June 5, and individuals at the north end of Lake Havasu June 8 and 10.
An early individual was seen on Lake Havasu February 1. My next record is of two at Pintail Slough February 20, although I had one in the interim time on the Parker Strip that apparently didn’t make it into eBird. My high count was a true spectacle of migration: in an hour and a half spent at Rotary Park March 4, I counted 3,189 Violet-green Swallows flying north. Since this species breeds in small numbers in the LCRV, my latest migrant is difficult to determine, but it was likely one at the north end of Lake Havasu May 18.
My earliest date was April 26, with two at the north end of Lake Havasu. My high count was also on my latest date this spring, with 21 at the north end May 18.
Excluding a few sightings in January on Lake Havasu, most likely a wintering individual, my earliest arrivals were two at the north end of Lake Havasu March 22. A big push occurred on April 30, when I counted 22 flying over CVCA near Cibola. I saw this species regularly through the first week of June, but after June 5 did not see another until June 11, with one over CVCA.
My FOS was over southern LHC February 24. After this sighting, I began seeing them regularly, although they did not show up in numbers until about mid-March.
This species seemed to depart early this spring; although I observed them regularly through April 9, I did not see another until two stopped at ‘Ahakhav April 27, my latest observation.
These little birds were notably absent as migrants this spring. While I recorded them fairly commonly in January, I only saw one in February, none in March, and my latest date was April 10, when one was last seen at ‘Ahakhav.
Most seemed to clear out in the beginning of May. After May 2, I did not observe another until my last of the season, one on the BWRNWR at Mosquito Flats May 14.
I was surprised to find this species commonly during spring migration in the LCRV. Since this seemed to be a good spring for them across Arizona, I’ll be interested to see how common they are next year. My observation dates range from May 7 (one in the Hualapais – not the LCRV but I’ll include it for an early migrant) through June 7 (with two remaining at ‘Ahakhav). My surveys at ‘Ahakhav consistently turned up a few birds, but my high count was May 30, when my survey on the BWRNWR in Mosquito Flats, covering a 400m x 400m area, turned up 15 individuals. In total, I observed a total of 42 individuals in the LCRV this spring.
During the period when Swainson’s Thrushes were moving through, Hermit Thrushes were already gone – my latest observation within the normal migration period was April 25, with one at ‘Ahakhav. Another was at ‘Ahakhav May 21, quite late for this species.
Pipits dropped off suddenly at the end of April. My latest observation was of three April 28 in Lake Havasu City.
Since this species was nearly absent from the LCRV this winter, it was possible to document their spring migration. My FOS for the LCRV, a flock of 28 passing by Lake Havasu April 20, was also my only count over 5 for the LCRV. Migration continued through spring; my latest was at ‘Ahakhav June 3, although others reported them later.
This species was uncommon through mid-May, when my latest was at Rotary Park May 17. Another was late at ‘Ahakhav June 1-3.
This warbler was fairly common during its short migration period. I observed Nashvilles from April 22 (five at ‘Ahakhav) through May 14 (one at BWRNWR, Mosquito Flats). Before the late bird on the Bill Will, my latest was at the north end of Lake Havasu April 26. My high count was eight, April 25 at ‘Ahakhav.
My earliest record was of two at BWRNWR, end of the road, April 11. The peak of migration fell in mid-May. May 17, 10 were at Rotary Park. May 18, 16 were at the north end of Lake Havasu. May 19, 15 were at Beal Lake.
Since this species was more common in winter than it was during migration, migration patterns were difficult to detect. Two notable pushes of migrants were: 81 at ‘Ahakhav April 16, and 31 at the north end of Lake Havasu May 4 (including 5 Myrtle Warblers). My latest migrant was at Parker Oasis May 21.
Another fairly common migrant, Townsend’s Warblers were steady from April 23 (CVCA) through June 5 (Parker Valley). I only had one individual most days in the field, although I had some days with 3-6 individuals. My count of 6 was from ‘Ahakhav Tribal Preserve, June 1.
This turned out to be a rather uncommon migrant; although counts of 2 were regular, I never had more than 3. Early and late dates, both with 2 individuals, were April 22 (‘Ahakhav) and June 2 (n. end Lake Havasu).
My early date of March 12 (‘Ahakhav) matched arrival dates in the rest of Arizona, but was very early for the LCRV. I did not record another until March 26, with two at Bermuda Pasture. Migration peaked May 23, with 50 passing through Parker Oasis. Counts up to 20 were regular this spring. My late date was June 8, with one at the north end of Lake Havasu.
My first record of a singing chat was on April 20, when two were at the north end of Lake Havasu. They subsequently became quite common in most riparian areas along the river.
This scarce migrant passed through between April 26 (Rotary Park) and May 19 (Beal Lake).
The pattern of Chipping Sparrows this spring is somewhat mysterious to me, enough that I want to wait another season before commenting on their migration. I can say that they seemed to be scarce migrants, and most were gone by the first week of May. One lingering individual in alternate plumage was at ‘Ahakhav May 29.
This is a scarcer migrant in the LCRV than Chipping, tending to stay further inland (?), but I can make some interesting notes about them. Since few were at Kohen Ranch on the CBC, 80 there April 11 seemed to be migrants. The last I saw was on the BWRNWR, at the end of the road, May 14.
This species dropped off quickly at the Island STP, where they wintered in good numbers, from 12 April 28 to two May 3.
Migration peaked around March 26, when I had ten at Bermuda Pasture and two at Pintail Slough. Most were gone by the second week of April (one at the north end April 8), but one was there again April 20.
The vast majority of wintering birds and migrants were Gambel’s, which took off by the first few days of May, my latest being at the north end of Lake Havasu May 4. I had a total of three Mountains in the LCRV, May 11-12.
This was another sparrow showing odd migration patterns this spring. With none present at ‘Ahakhav over the winter, twelve Oregon Juncos there February 13 seemed to be migrants. Another flock was there March 12, consisting of eleven Oregon, two Slate-colored, and two Cassiar Juncos. Finally, a Cassiar was at the north end of Lake Havasu March 31.
My earliest were six at BWRNWR, Mosquito Flats April 17. I had high counts of 12 twice, first at Parker Oasis May 21, then at ‘Ahakhav May 29. My latest were two at ‘Ahakhav June 7.
The fact that my FOS for this species were four in one day in the Hualapai Mountains suggests that I missed the earliest arrivals of migrants in the LCRV. Still, I’ll note that my earliest in the LCRV were two at CVCA April 23. My high count was only five, at BWRNWR, end of the road May 14. My latest record was of two at CVCA June 11.
My first sighting of this species was right about on time, two males at Cibola, CVCA April 23.
This species was seen in small numbers, but regularly, from April 26 (three at the north end of Lake Havasu) through June 4 (two at CVCA). I recorded a big push May 18, when 15 were at the north end of Lake Havasu.
This species seemed to disappear without my noticing! My latest observation was of 30 at ‘Ahakhav April 16.
The earliest I recorded cowbirds away from wintering areas was March 15, when one started singing in Rotary Park.
This is a rather scarce migrant and breeder in the LCRV, but my FOS, on the BWRNWR April 11, seems about right for an early arrival.
These birds arrived in early April; my FOS were two at Bermuda Pasture April 4. Numbers increased by the last week of April.
This irruptive species was scarce in the LCRV this year, occurring only as migrants, not wintering (at least north of Quartzsite). I heard one flying over Rotary Park April 9, and had two at ‘Ahakhav the next day.
The movements of LAGOs this spring is puzzling to me. I observed three nests being built at ‘Ahakhav, each of which was promptly abandoned. After the first nest was abandoned, the birds were absent from the preserve for a month. I did note a push of migrants April 10, with twelve at ‘Ahakhav, dropping to three there April 16.
This winter was not a good one for wintering finches in the LCRV, and American Goldfinches were absent as well. Small flocks were noted in mid and late March, with 1-2 lingering at ‘Ahakhav through May 2.
Splendid! I hope you put sunblock on the troll for the kayaking 😉