Catching the Wind: Observing Migratory Events

Good flying days approach for migrating monarchs along the Atlantic Coast!


Flyways and Cold Fronts

As the daylight hours shorten and the temperatures cool, some of us are already thinking of how to escape to warmer climates. If you are a migratory bird or a monarch butterfly, heading south is a necessity. Capturing the last sips of energy rich nectar from fading flowers, migratory birds and insects follow migratory pathways, or flyways. There are four major flyways in North America: Atlantic, Mississippi, Central, and Pacific Flyways. In the U.S. and Canada, a constellation of organizations have established locations where the public can watch peak migratory events. Hawkwatch International and Hawk Migration Association of North American are two such groups. Various state Audubon organizations have also established observatories at prime locations for viewing migration. National and Provincial Parks also provide opportunities to watch migratory species fly by. 

Despite these well-placed observatories, weather plays a critical role in catching peak migration events. Migration watchers often find that migratory birds and monarch butterflies catch the tailwinds the day of and day after a cold front passes through a location. Looks like these days are upon those watchers living along the Atlantic Coast. Don’t forget to report your observations to Journey North. 

From New Jersey Audubon Cape May Bird Observatory

Situated along the shores of the Atlantic Ocean, the New Jersey (NJ) Audubon Cape May Bird Observatory provides an ideal location for bird and butterfly watching, especially during fall migration. Cape May is a narrow peninsula with Delaware Bay on the west and the Atlantic Ocean to the east. The Cape May peninsula forms a bird funnel, directing migrating songbirds, hawks, and monarchs along the coastline during spring and fall migration. 

Mark Garland, Director of the Observatory’s Monarch Monitoring Project, provided the following information for our Journey North community scientists: 

Catch the Migration

Adult monarchs are found around Cape May Point in variable numbers every day from mid-August until the first hard freeze, which usually occurs in late October or early November.  

Volunteer Power

As the monarch numbers increased during August of this year, before our formal monarch butterfly censuses began, Karen and Bob McClennen performed some informal censuses around Cape May Point, taking the initiative to send results of these counts to Journey North. Karen and Bob have been our most active volunteers for several years, and we benefit greatly from their enthusiasm for monarch and the work that we conduct.

The Road Census

With monarchs present daily and in numbers that would be impossible to count, we rely on our road census, a sampling technique that was developed by Dick Walton and Lincoln Brower in the early 1990s. A vital element to the Cape May Monarch Monitoring Project is our road census, which gives us a method to compare the numbers of monarchs around the Cape from week to week and from year to year. A member of our team drives a designated 5 mile route 3 times daily at a slow speed, counting every monarch seen along the way. Our first three weeks of census are complete, and the numbers verify our hunch that the monarch numbers have been a bit below average up to this point of the season. Looking more closely at the numbers for this, year 30 of the census, here’s one way to look at how this year compares to the previous ones. Week one ranked 12th compared to other first weeks, but the highest week one count since 2010 (21.8 then, 18.8 now). Week two ranked 16th, week three ranked 23rd.

This isn’t really a surprise, since we’ve had a lot of warm weather and winds from the south or from the east. Monarchs usually migrate when the winds are blowing from the north, and a westerly component to the wind often brings more monarchs toward the coast, and then down into Cape May Point. In recent years we’ve had a lot of unfavorable winds during the first half of September, and it’s been a while since we have seen many monarchs on those days.

Cold Front

It all might be about to change. A big cold front is predicted to arrive on Thursday, bringing a lot of rain, but clearly out on Friday, the first of four consecutive days when northwest winds are predicted. These are the conditions that frequently bring big numbers of monarchs into Cape May. Can we guarantee lots of monarchs during the next few days? Of course not, nature isn’t ever fully predictable, but we’re hopeful, and I can guarantee that our team will be out in the field, ready to count, study, tag, and teach about monarchs, however many there may be. 

Follow Karen and Bob McClennen’s reporting from Cape May as the momentum of monarch migration builds.  

And remember to report your observations to Journey North. Happy fall migration!