Geographic Reorientation Case Studies
Locational Reorientation Case Studies:
The Bluff, Huron, Ontario - 6 May 2018 (east-west?)
ebird checklist - google maps for location - archived weather conditions - surface map
Key Species:
22 Northern Flicker
4 Blue-gray Gnatcatcher
345 American Goldfinch
108 Bobolink
30 Yellow Warbler
The species noted above may be reasonable examples of east-west reorienting migrants. Gentle east/southeast winds should not necessarily have "pushed" migrants against the shoreline; however, a concentration has occurred nonetheless. Birds may have been reorienting westward, perhaps to breeding territories in Michigan, leading to a low but steady number of birds moving south past this location along the shoreline. Northbound birds may also have been taking short east to north reorientation flights, leading to a mix of birds going both north and south past the watch point.
It is also worth noting the overnight weather, which was suitable but not exceptional, for nocturnal migration. This combined with a migration that was generally "on-time", likely lead to this flight having relatively low numbers yet interesting species involvement.
Point Pelee (Tip), Essex, Ontario - 8 May 2014 (north-south?)
ebird checklist - google maps for location - archived weather conditions - surface map
Key Species:
1 Blue Grosbeak
32 Indigo Bunting
14 Eastern Kingbird
The species listed above are reasonable examples of north-south (in this case, south) reorienting migrants. This was the first significant surge of migrants (note strong warm front) in May 2014, which had been somewhat "behind schedule" until this day. The presence of a Blue Grosbeak, generally considered an "overshoot" in the region, gives some credibility to it perhaps arriving overnight and immediately undertaking a southward reorientation that morning (although this is not 100% confirmable).
The generally low numbers of other southbound birds (i.e., 32 Indigo Bunting, 14 Eastern Kingbird) supports the potential that a low to moderate number of birds had overshot their intended destination (presumably nesting territories in Ohio) and were also correcting south. The general ratios of obvious "overshoot" migrants in morning flight at Point Pelee such as Blue Grosbeak or Summer Tanager to "cryptic" overshoots such as Indigo Bunting, Eastern Kingbird or Yellow Warbler hints that many or all may be overshoots during flights such as the one recorded on May 8, 2014.
