Checklist S69283462

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Owner Sean Williams

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Nocturnal migration had been severely stalled by consistent northern winds and precipitation for the previous two weeks. Warm temperatures and southwest winds on the night of May 14th produced a large movement. The night of May 15th began with similar conditions, although a severe storm front moved through in the middle of the night, shutting down migration in its tracks and putting many birds over water. These birds then quickly sought any land mass, which for many was Cape Cod.

Upon driving into the entrance of the airport parking lot at 05:15, 50 birds flushed in my headlights and I slammed on the brakes. There were a couple hundred birds, mostly sparrows, on the pavement and in bushes. Yellow-rumped Warblers, Northern Parulas, a Cape May, and a Nashville were scattered on the ground as well. Their feathers were wet and matted, with many birds shaking off. I spent the next hour or two poring through the sparrows, counting and picking through for rarities. The slight majority of sparrows were Savannah, with the rest made up by Lincoln’s and White-crowned. At the same time, groups of 10-20 warblers were arriving from the west and north, clearly coming in off the ocean. The groups were fairly high- 100-200 m above the ground. Upon positioning themselves directly over the thicket, they began to free fall vertically in unison with wings completely tucked. The tightness and unity of their movements were remarkable- unlike the typical loose form of warbler flocks, and instead like a school of fish. About 10 feet over the thickets, they broke from their synchronized formation into different directions, darting into the vegetation at surprising velocity, like little feathered bullets. By 07:00, warbler groups started flying in from the east and continuing west. Some were flying high at first when it was still clouded over and the wind was calm. At 07:15-07:30, the distant northern skies were clearing, the sun peeked out, and a 5 mph northern breeze picked up. The warblers then started flying much closer to the ground, so I positioned myself atop a dune. Most warblers were flying between eye level to 15 m high. At 07:55, the trickle of a dozen or two warblers per minute turned into a stream when a group of 40 birds passed over, shortly followed by another 50. For the next 30 minutes, a solid flow of warblers came from the east to west, passing by a north-south imaginary line at a rate of 100 individuals/minute. Some were flying directly overhead, and some to the north as well as the south. The birds to the south were close, although to the north they were flying closer to the dunes, about 150 m away. Around 08:30-08:45, Peter Trimble joined when the wind increased further from the northwest (10-15 mph), and the flight line along the dunes to the north dissipated and concentrated birds to flying low to the ground along the leeside of the dunes below me. The peak numbers dissipated just after 9 am, and slowly tapered off until we left at 10:30 am.

Identification methodology focused on identifying close (<15 m) warblers naked eye and further warblers up to 50 m away in binoculars with good light. The far line of ~1000 warblers along the northern dunes mostly went unidentified.

Counting methodology consisted of tallying birds as they passed an imaginary north-south line. For all species, I updated individual numbers every 5-10 minutes. As well, I was keeping an overall warbler individual tally counting by 10’s. Between 07:00-10:15, I tallied 4880 warblers.

05:15-06:00: heavily overcast with low cloud cover. Calm.
06:00-07:00: cloud ceiling increasing significantly in height. Distant north and east horizon clearing up and sun starting to poke through. 5mph breeze picking up from northwest.
07:00-08:00: clouds moving south and sky transitioning to clear. Still fairly calm.
08:00-09:00: Mostly clear skies, with breeze intensifying to 10 mph
09:00-10:00: Mostly clear skies and northwest wind consistent


  1. Number observed: 2
  2. Number observed: 1

    Details: Local flying out of tall wet thicket.

  3. Number observed: 3
  4. Number observed: 2

    Details: Flying into marsh at airport

  5. Number observed: 8

    Details: Flying east to west

  6. Number observed: 35

    Details: Flying west to east

  7. Number observed: 4
  8. Number observed: 2
  9. Number observed: 5
  10. Number observed: 1

    Details: In wet thickets around airport

  11. Number observed: 8

    Details: Several flying over the airfield early morning, not heading in any set direction

  12. Number observed: 2

    Details: One early morning buzzed over the thickets, another later flying east to west during morning flight

  13. Number observed: 4
  14. Number observed: 1
  15. Number observed: 2
  16. Number observed: 5
  17. peep sp.

    Number observed: 10
  18. Number observed: 1
  19. Short-billed/Long-billed Dowitcher

    Number observed: 2
  20. Number observed: 1
  21. Number observed: 14

    Details: Several calling and flying throughout the morning. Most heading west or north, a few circling over to the airport, but I tried to not double count these.

  22. Number observed: 12

    Details: Scattered individuals calling and flying, most east to west

  23. Number observed: 1
  24. Number observed: 6

    Details: Single group flying east to west

  25. Number observed: 40
  26. Number observed: 100
  27. Number observed: 15
  28. Number observed: 4
  29. Number observed: 6
  30. Number observed: 1

    Details: One in complete non-breeding plumage flying south to north

  31. Number observed: 6
  32. Number observed: 40

    Details: Seen beyond the dunes moving along the beach

  33. Number observed: 60

    Details: Several groups flying east to west

  34. Number observed: 3
  35. Number observed: 2
  36. Number observed: 9

    Details: Interesting movement of Green Herons, which typically are uncommon on the Cape in the spring. Several individuals and pairs were flying west, and some even dropping into the pines and stunted trees over water around the airport. Out of the nine individuals, all three that were aged were second years. Given that GRHE populations likely are composed are far less than half of second years, this is an interesting pattern that might suggest second years were more prone to being blown off course.

  37. Number observed: 2

    Details: Two immatures early morning flying over airport

  38. Number observed: 30
  39. Number observed: 2
  40. Number observed: 1
  41. Number observed: 2
  42. Number observed: 1
  43. Number observed: 2
  44. Number observed: 2
  45. Number observed: 1

    Details: Heard only from the east, careful to not be tricked by mocker

  46. Number observed: 1

    Details: Calling from pines mid-morning

  47. Number observed: 2
  48. Number observed: 1
  49. Number observed: 3
  50. Number observed: 1

    Details: Peculiar to see this bird flying east to west while surrounded by a large warbler flock. The warblers did not react despite many individuals being within 50 ft of this falcon. Everyone shared the same mission. The flight style was different from the typical steady, powerful wingbeats. Instead, this bird was flying slightly undulatorily by rapidly flapping its wings and then dropping.

  51. Number observed: 1

    Details: Rare on Cape Cod. One flying low east to west. A large flycatcher that appeared kingbird-like, but flight style was more erratic with deeper wingbeats as opposed to the jittery wingbeats and more direct flight trajectory of kingbirds. The breast was dark and white wrapped around the undertail coverts to the base of the tail.

  52. Alder/Willow Flycatcher (Traill's Flycatcher)

    Number observed: 1

    Details: One large Empidonax flycatcher with a long, heavy bill relatively to the many Leasts nearby and a weak eyering. Silent.

  53. Number observed: 25

    Details: 12 around the airport parking lot, and the rest in morning flight. Long-tailed flycatchers with wingbars, a small bill, and a thick white eyering. Many giving upslurred “whit” calls around the parking lot.

  54. Number observed: 2

    Details: In morning flight very early

  55. Number observed: 210

    Details: Amazing flight of kingbirds. Mostly loose groups of 10-15 individuals flying east to west, calling in flight. One large group of 40+ birds flew alongside the northern dunes. Photos show that most are males.

  56. Number observed: 1

    Details: Singing around the parking lot just after dawn

  57. Number observed: 45

    Details: Strong numbers in morning flight. Picked out among the warblers by the relatively large size, large and round head, and thick bill. In binoculars, the spectacles and wingbars helped with the ID.

  58. Number observed: 2

    Details: Both in morning flight. Photos of both.

  59. Number observed: 20

    Details: One group flying along the dunes very early in the morning. Later, a small group moved east to west just above the pines around 9:30 am, long after most birds had already moved through.

  60. Number observed: 4
  61. Number observed: 2
  62. Number observed: 1

    Details: Heard croaking in the distance at some point during the morning flight

  63. Number observed: 6
  64. Number observed: 3

    Details: Flyovers, west to east; clearly locals and not in morning flight

  65. Number observed: 1
  66. Number observed: 10
  67. Number observed: 2
  68. Number observed: 30
  69. Number observed: 3

    Details: In thickets around parking lot; one in morning flight moving low through bushes

  70. Number observed: 1

    Details: Heard from pines mid-morning

  71. Number observed: 15

    Details: Most in morning flight

  72. Number observed: 1

    Details: Thickets around parking lot

  73. Number observed: 2
  74. Number observed: 25

    Details: Several around parking lot, none in morning flight

  75. Number observed: 1

    Details: Singing around parking lot early morning

  76. Number observed: 2
  77. Number observed: 2

    Details: Among a few thrushes in the parking lot early morning; none in morning flight

  78. Number observed: 3

    Details: Among a few thrushes in the parking lot early morning; none in morning flight

  79. Number observed: 1

    Details: Calling from thicket early morning

  80. Number observed: 20
  81. Number observed: 45

    Details: A few small groups flying in different directions, some south to north and another west to east

  82. Number observed: 5
  83. Number observed: 1

    Details: Late. One flying east to west and over to the airport. Another heard later may have been the same individual. Long-tailed passerine giving high, thin, monotone seetseetseet.

  84. Number observed: 3
  85. Number observed: 1
  86. Number observed: 10
  87. Number observed: 1

    Details: Rare and late. One flyover giving harsh rattle, though not harsh enough for Smith’s. No plumage seen, but observed a small, short-tailed, and thick-billed passerine with undulatory flight.

  88. Number observed: 25

    Details: Most on the ground, a few in morning flight

  89. Number observed: 2

    Details: Rare in the spring. Two seen in separate corners of the parking lot in close succession around 05:30. The first one was still wet and did a little shake. Unclear whether the birds photographed are the same or different. The first was photographed at 05:30, the second at 07:00.

  90. Number observed: 4
  91. Number observed: 58

    Details: Amazing numbers scattered around every corner of the parking lot. All in clean adult plumage. The main concentration was in the grass seed patches, but still many scattered in bushes and on pavement. Many singing. A few were moving in the morning flight as well, but were hopping between bushes low to the ground rather than flying with the warblers.

  92. Number observed: 1

    Details: Very rare, especially in the spring. One individual picked out with completely pale lores, and a small bill that was a brigther pinkish orange compared to nearby White-crowneds. Seen several times.

  93. Number observed: 12
  94. Number observed: 1

    Details: Large, pale, streaky sparrow with completely white outer tail feathers flushing in front of me. Only seen very early. This individual seemed to depart into the dunes with some of the Savannahs.

  95. Number observed: 250

    Details: Huge numbers around the parking lot early morning. Half or more scattered into the dunes in the first hour. Only a few were seen in morning flight.

  96. Number observed: 10

    Details: Including one that appeared visually different to me- pale and reddish with sparse flank streaking.

  97. Number observed: 66

    Details: Amazing concentrations. Lincoln’s Sparrows were everywhere. In bushes, in the road, and in grass. There were some scattered groups of 3-5 individuals, and many other singles. A minimum of 30 were counted on the grass seed, on the pavement, and in bushes around the airport. At one point there were 16 in view on the grass seed. Another 15 were seen along the edge of the west thicket, and the rest were scattered in various other places around the dunes and along the path to the maintenance area. This truly was a spectacle to see so many in one location on the East Coast in the spring.

  98. Number observed: 5
  99. Number observed: 15
  100. Number observed: 122

    Details: Several large flocks flying west to east. Some flocks had mostly males that often would give partial songs in flight, and one flock was mostly females.

  101. Number observed: 6

    Details: All local adult males and a few females; none in morning flight

  102. Number observed: 88

    Details: Many around the airport parking lot, and some flying west to east with the other migrants. Most were females or young males.

  103. Number observed: 40
  104. Number observed: 15
  105. Number observed: 60
  106. Number observed: 23

    Details: Several walking around on the ground in bushes around the parking lot, only a couple singing throughout the morning. Relatively few in morning flight.

  107. Number observed: 35
  108. Number observed: 1

    Details: One in morning flight

  109. Number observed: 420

    Details: All in morning flight. Exceptional numbers flying with parulas and Yellow-rumps, roughly 50/50 males and females. These were identified primarily by the flight profile- somewhat erratic movement of a short-tailed warbler with a long-bill. Most seen in sufficient light to detect the black and striping. Some were giving flight calls, but relatively less often than others. The flight call was buzzier and shorter relative to other flight notes.

  110. Number observed: 2

    Details: Hard to identify, but in good light the males’ smooth green wings contrast well with a steely blue cap.

  111. Number observed: 1

    Details: Rare in spring. In morning flight.

  112. Number observed: 60

    Details: Most in morning flight, a few around the parking lot. Hard to identify, but in good light the smooth yellow body and greenish back narrow it down to the “yellow” warbler group, and when close enough the males’ blue heads can set them apart from the others.

  113. Number observed: 120

    Details: Very few in early morning flight. Most were littered throughout the thickets and pines. Almost none singing, but many calling.

  114. Number observed: 30

    Details: About two-thirds male, some female.

  115. Number observed: 181

    Details: About two-thirds male. Amazing movement. I kept a particularly accurate tally on these since they've historically been scarce in Massachusetts. The females are a bit harder to identify in flight unless the yellow rump and streaked yellow body can be seen. The flight notes helped with identification, which are a soft, ringing buzz, often downslurred.

  116. Number observed: 890

    Details: A few in bushes, the rest in morning flight. Amazing. These were distinctive by flight profile and by call. The call is a short, descending, high pitched seep with no buzzy quality. It’s fairly reminiscent to some parid sounds. They were picked out visually by their large-headed and short-tailed proportions with fairly erratic flight, and in good light they appeared from below as dark-throated and white-bellied, with a white undertail appearing as a small window with a clean black border.

  117. Number observed: 45

    Details: All in morning flight. Males are distinctive in flight, females not so much except when the undertail can be seen well. The flight call is not distinctive either.

  118. Number observed: 114

    Details: Mostly males, about 10% females. Amazing movement. About half came through early, prior to the peak of the morning flight, before 08:00. The rest were scattered over the next hour and a half. I kept a particularly accurate tally on this species since historically they have been one of the least common warblers in Massachusetts. The males are very distinctive in flight as the black face contrasts strongly with the buffy nape. The Bay-breasteds were particularly noteworthy in their flock cohesiveness. This species more so than others traveled together in flocks. Most Bay-breasted flocks were of 3-6 birds. One exceptional flock of 50 warblers flew by, the majority of which were Bay-breasted Warblers, and the rest were mostly Cape Mays, with a few Yellow-rumps mixed in too. Some Bay-breasted groups paused in a small scrub oak to glean insects, landing on the east side of the tree. Upon hopping through to the westernmost branches, they lifted off and departed together.

  119. Number observed: 17

    Details: Mostly males in morning flight; only a couple females.

  120. Number observed: 40

    Details: Most around the edges of the parking lot, relatively few in morning flight, but females are hard to ID.

  121. Number observed: 26

    Details: All males, relatively very few in morning flight.

  122. Number observed: 45

    Details: All males. I did not see any females, although can be difficult to identify in flight.

  123. Number observed: 140

    Details: A few early morning around the parking lot, the rest were in morning flight. Mostly males identified in flight. The females are hard to pick out unless the small white wing patch is seen well.

  124. Number observed: 1

    Details: Rare in spring, but there have been more around this year. In bushes early morning. The flanks were completely brownish with darker streaking and no sign of yellow or red in the flanks.

  125. Number observed: 8

    Details: None in morning flight? Local males, several singing, and some females.

  126. Number observed: 770

    Details: Only two early morning in the bushes, the rest in morning flight, with a clear pulse early in flight, and then again later. These were medium-sized, long-tailed warblers with a relatively linear, slower flight style.

  127. Number observed: 12

    Details: A few locals singing, rest in morning flight.

  128. Number observed: 160

    Details: About 15 on ground and in bushes early morning. The rest were in morning flight. These were identified by their mostly white undertail and belly, with a contrasting black throat and yellow face.

  129. Number observed: 1

    Details: One male in morning flight, flying low.

  130. Number observed: 34

    Details: Eight in bushes early morning; rest in morning flight. Almost all males in morning flight and few females.

  131. warbler sp. (Parulidae sp.)

    Number observed: 1900

    Details: Unidentified warblers, with about half of these coming from the distant flight line. I'm adding several photos here of mostly NOPA, BAWW, and YRWA. A few audio files have been added of general flight calls.

  132. Number observed: 2

    Details: A large yellow-orange passerine flying along with the other passerines during morning flight. Smooth coloration on the body and wings, a thick bill, and a short tail with orange uppertail coverts.

    Thanks to Jeremiah Trimble for catching a second bird, a female, represented by the second set of photos.

  133. Number observed: 26

    Details: All in morning flight. Almost all females flying, except three males.

  134. Number observed: 2
  135. Number observed: 19

    Details: About half in morning flight, with several in thickets around the parking lot as well

  136. Number observed: 3

    Details: In morning flight

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