Geography & Weather

At a basic level, geography and weather conditions define birding "hotspots" and this is true with morning flight. Understanding of how they affect migration lets you predict the right places and days to be in the field, and documenting flights helps us all improve our understanding of the phenomenon. 

Check out the fallout tools page for all of our favourite weather sources. 

Key Considerations

Consider what species are currently migrating as well as their propensity to undertake morning flight. When conditions are highly suitable, perhaps even confirmed by radar observations, an evaluation of geography and weather can take place: 

• What type of flight is likely to unfold? 

• Is the morning weather suitable for the flight to occur? 

• What geography could encourage or concentrate the movement?

Weather 

Use tools like birdcast to understand the when suitable nocturnal migratory conditions are predicted or occurring. Verify that nocturnal movements are underway in real-time with birdcast / radar imagery. Use weather model data or local forecasts to predict the morning weather. The Great Lakes Operational Forecast Systems and/or marine forecasts are useful for more accurate conditions along our lakeshores. Birds flying into a moderate headwind may be lower, allowing for better viewing. Sunlight at your back also aids in identification. 

Always remember that localized forecasts in complex areas (such as near the Great Lakes with competing land/water temperatures and winds) is very difficult and some trial and error will be required to better understand your local conditions. It's the fog that always gets me! 

Consider Types of Flight

Covered on its own page, make a prediction about what flight mode is likely, based on your awareness of how migration is progressing AND the weather forecast. Briefly,

• Diurnal Migration: with songbirds migrating during the day, you'll most likely encounter them on seasonally productive weather any time during spring (warm) or fall (cool) migration. Moderate tolerance to inclement weather. Headwinds may keep birds lower. 

• Onward Migration: most common in spring, flights are more noticeable close to a warm front during easterly winds, where headwinds may keep birds lower to the ground. Southerly winds in spring are also likely productive, but may cause northward moving birds to fly higher. Moderate tolerance to inclement weather. Rare in fall, often on north winds which leads to a high flight. It is even rarer to get a large flight in fall on southerly winds which would help keep birds lower 

• Geographic Reorientation: spring and fall. Variable and harder to predict, pending slight differences in migration timing, migration progress and concentration effects for a given species on a given day. Moderate to low tolerance to inclement weather. 

• Reverse Migration: Spring. Often requires well below temperatures and/or inclement weather, including snow in March/April. 

• True Morning Flight: Most common in fall. Low tolerance to inclement weather. Best under sunny skies and light to moderate winds. 

Keep in mind that all species have their own tolerance as to when they will or won't fly - or if they will fly into the wind or get pushed by the wind, etc. Practice makes progress here. 

Geography

By now you've determined:

• The species that are currently migrating.

• How likely they are to undertake morning flight. 

• That a migration event is likely (2-3 days away) or happening (the night before). 

• The type of flight that is likely to happen. 

• That the morning weather conditions are suitable for a flight. 

Now a review of geography to find an ideal location to document the movement! Although keep in mind that smaller numbers of birds undertaking morning flight can be seen just about anywhere following a strong overnight migration. A breakdown by each type of flight: 

True Diurnal Migration

• Common spring and fall. Birds moving in their expected direction under suitable conditions. Fall movements may involve adverse weather. 

• Species-tolerance needs to be considered when assessing geography for concentration. Many diurnal migrants can be observed inland, concentrating more along shorelines or at points of land when pushed there by the wind. 

• May be more likely to follow habitat features at inland sites (i.e., rivers, hedgerows, woodlots, etc.) than other flight types.  

Per above - stronger winds will enhance shoreline concentration for diurnal migration in spring and fall. 

Onward Migration 

• Most common in spring when there is more urgency to arrived on territory, generally when birds are "behind schedule". Flights into the wind are more easily viewed than birds flying with the wind (when they gain significant height).  

• Will fly up against shorelines or other geographic features in spring and fall, and will occasionally "hover" into the wind at north-facing points in spring. 

• May be widespread and involve significant numbers of birds. 

Geographic Reorientation

• Most common in spring when birds are returning to their territories. Largest numbers are during mass-arrival events of local breeding species. 

• Will readily fly up against/along shoreline features. Encountering "dead end" points of land may alter their behaviour, including circling or low movements through vegetation. 

• Typically only occurs in pleasant weather (i.e., not adverse conditions). Occurs in any wind condition, but headwinds may be required to keep birds lower for you to observe them

Reverse Migration

• Generally a spring event, as adverse conditions in fall are generally just triggering diurnal migration. 

• Two factors are often required, the initial presence of seasonal or ahead-of-seasonal migrants, followed by adverse weather that triggers an emergency reverse migration. This may be deep snow for earlier migrants and unseasonable cold and strong winds for later migrants. 

• Will concentrate along shoreline geographies. May recognize "dead ends" and entirely stop their movements more readily than other flight types. 

True Morning Flight

• More common in fall than spring. Generally occurs with birds flying INTO the wind, very rarely being pushed against their will. 

• Geographically, birds are flying into conditions they are comfortable with. They will frequently avoid making flights "along" shorelines where it can be avoided (i.e., they move inland). 

• Geographies that concentrate birds (i.e., pinch points) without suitable alternatives may yield the highest numbers. 

• Rarely, under suitable wind and geography, birds will fly into an "end point" and hover into the wind. 

   Case Studies: 

Diurnal Migration 

• 27 Oct 2022: classic-fare fall diurnal migration of passerines (blackbirds, crows, etc.) concentrated by the shoreline of Lake Erie and strong winds. 

• 19 Sep 2018: an inland flight of 800+ Blue Jays, indicating that shoreline concentration may require stronger winds to push birds closer to shorelines, and/or geographic "pinch points" to be fully effective with some species. Also demonstrates the potential for "inland" flights on calmer weather, with potential for birds to follow habitat features. 

• 8 Apr 2019: a classic spring migration of diurnal migrant passerines (blackbirds, American Robin, Common Redpoll, etc). concentrated by the shore of Lake Ontario. 

Onward Migration 

• 12 May 2023: Evidence of a notable mid-May "onward" migration of multiple warbler species. Light winds and clear skies likely led to an onward migration that was higher than what would normally be detected by an observer. A bit of luck and a northeast facing point of land allowed for enough concentration for the birds to be noticed. 

• 7 May 2023: A more traditionally observed "onward" migration of species like Yellow-rumped Warbler or Eastern Kingbird. With birds flying into a stronger easterly wind, they were low enough to be documented/counted by observers. Concentration for this watch was provided by the wind direction/intensity and the shoreline geography. 

Geographic Reorientation

• 17 May 2017: assumed south (or east) geographic reorientation of passerines concentrated both by the N-S orientation of Lake Huron and also the "tip" of Tawas Point. 

• 29 May 2013: assumed geographic reorientation of Cedar Waxwings which have ended up on the "wrong" side of Lake Michigan and are returning west. Concentrated by their need to "round" the shoreline. 

Reverse Migration

• 31 Mar 1987: classic early season adverse weather reverse migration along Lake Ontario. Shoreline concentration occurring. 

• 9 May 2019: a localized event, where an on-time to advanced migration state may have triggered a southbound movement when newly arrived migrants encountered cold, damp lake winds and flew in search of better foraging conditions/habitats. The geography at the tip provided notable concentration effects. Further assumptions include: 

  • Species such as Yellow-rumped Warbler occurred in lower numbers at the Tip due to either their tolerance of the cooler weather, and/or that they flew north out of the park in an "onward" migration. The weather wasn't poor enough for them to flee or move south. 

  • That a flight such as this would not occur in a "later" spring when birds were "behind" schedule (i.e., note the higher numbers of "mid May" species such as Magnolia, Bay-breasted or Blackburnian Warblers). 

  • Fallout conditions locally make this flight appear larger and more significant than the weather or geography would imply due to a large "source" of recently arrived birds. 

True Morning Flight 

• • • 14 Sep 2022: a large fall flight of expected species. Geography helped concentrate birds both due to wind direction (flying into a NW wind, bringing them N along the shoreline) and also due to the "pinch point" at the north end of Rondeau Park, preventing any meaningful "escape" inland. 

    • 29 Sep 2018: a similar example to Sep 14, 2022 above with different wind (west to west-southwest) and geography. Yet the outcome is similar with a flight direction into the wind combined with a geographic pinch-point to concentrate birds. 

    • 6 Oct 2009: a large movement of Yellow-rumped Warblers following habitat features rather than shorelines. Flight direction was still into the wind. 

    • 24 Aug 2019: most birds have moved inland away from Lake Erie; however, Blue-gray Gnatcatchers have been pushed backwards in flight but are not deterred (i.e., they are not landing). A demonstration of how open shorelines may provide poor geographic concentration with stronger flying species for these types of flight.