Morning Flight
Types of Flight

Some theories on why birds undertake morning flight, and how to potentially classify the "reason" for undertaking their flights, are provided below. It is worth noting that these flight types can overlap depending on local geography and weather conditions. These were developed in isolation from theories developed at well studied locations like Cape May, with the hope that our abundant shorelines and geographic features could yield novel ideas. 

Comments are greatly appreciated - these pages will be updated as our understanding improves! Potential (arbitrarily named) "types of flight" include: 


Diurnal Migration: A case could be made that this *is* or *isn't* part of the morning flight phenomenon. This type occurs with birds that are utilizing daytime conditions to advance their forward migration. These passerines or near-passerines are species which migrate during the day and are flying in their expected direction (i.e., flying north in spring or south in fall). Common with blackbirds, finches, etc. Click for Case Studies demonstrating this type of flight. 


Onward Flights: species more typically considered nocturnal migrants, or those which can migrate both during the day and at night, which have continued their nocturnal migration into the daylight hours. Most noticeable with passerines (e.g., Yellow-rumped Warbler, Eastern Kingbird, etc.) locally. Click for Case Studies.


Geographic Reorientation: following a significant nocturnal flight, birds may find themselves somewhat to significantly off course, close to their breeding territories or in less-desirable habitat. They may then undertake a deliberate diurnal flight in order to correct their situation. Reorientation appears possible in any direction (i.e., north-south or east-west). An array of species will variably undertake a "geographic reorientation" flight in spring and/or fall; however, locally, there can be especially strong "breeding territory" reorientation flights in spring. Click for Case Studies. 


Reverse Migration: under specific conditions, birds may undertake a large / true reverse migration, where they are displaced by adverse weather conditions (i.e., significant cold weather in spring, fleeing severe weather). Low numbers may also return south following a failed attempt to find a mate or nest. Adverse weather flights can yield significant numbers of birds and are most common in spring. Fall movements may be related to other "types" below rather than true reverse movements. Click for Case Studies. 


True Morning Flight

A final "type" is... a possible biological propensity to undertake morning flight... Dedicated research would likely be required to advance this speculation; however, some initial possible reasons could include: 

This flight-type is much more noticeable locally during fall migration than spring. It would be interesting to know if these behaviors occur elsewhere at different times or ways (i.e., is it observed by these species soon after leaving their wintering grounds). Species which may have this predisposition to undertake these "true morning flights" include Blackpoll Warbler, Cape May Warbler, Tennessee Warbler, and other neotropic migrants. Click for Case Studies.

Other

Post-Roost Flights

Arguably not part of the true morning flight phenomenon; however, many birders documenting a flight will likely be counting some birds/species which are moving between nocturnal roosts and diurnal foraging locations. Foraging sites may be influenced by weather conditions, leading to daily variation in movements past a watch-location. Species which frequently undertake these daily movements include Swallows, Martins, Blackbirds, Mourning Doves, American Robin, and more. Click for Case Studies demonstrating this type of flight. 


Emergency Flights

Also not part of the true morning flight phenomenon, birders will sometimes encounter passerines and other birds in flight over open water, making notable effort to return to land. These birds have likely experienced unintended drift or displacement over water, frequently but not always due to strong winds or adverse conditions (e.g., rain or fog). They are facing significant danger due to exhaustion and/or depredation from raptors or gulls. Species encountered often include Kinglets, Creepers, Winter Wren, White-throated Sparrow and Dark-eyed Junco. Click for Case Studies. 


DETAILED CASE STUDIES 

The Bluff, Lake Huron, Ontario - May 9-13, 2022

Local migration in early May 2022 could be considered somewhat "behind schedule" with cooler temperatures persisting until May 9. At this time, reasonable stalled or blocked weather patterns shifted into more ideal migratory conditions, allowing for several consecutive days of ideal migratory conditions. These resulting conditions were also ideal for observing morning flight on Lake Huron and an effort was made to monitor how the species, abundance and direction varied day to day. Within a few days, migration had not only "caught up" to seasonal expectations, but had become "ahead" of the normal schedule. Ultimately, birds were recorded undertaking morning flight for a variety of assumed reasons including true diurnal migrants, onward migrants, geographic reorientation movements, and perhaps true morning flight behaviours. An overview is provided on it's own page here. 

Point Pelee (Blue Heron), Lake Erie, Ontario - August 31 - September 2, 2022

Multiple days of ideal weather conditions during high-season for neotropic passerine migration in southern Ontario. A number of potential flight-types were recorded including some True Diurnal Migration, variable True Morning Flight possibilities and Post-Roost Flight. This is provided as the last detailed case study due to some of the unexplained observations from September 2. There is always more to learn! The overview is provided on it's own page here.