Monarch PEAK Migration
Sightings report image

Date: 09/27/2020

Number: 82

Consistent northbound movement from lighthouse from 9:12am to 10:12am. Light northeast winds at 5MPH. 1.4 monarchs per minute. Most of the individuals came off the bay from the southwest, came to shore, then proceed north along the marsh. So they're going into the wind on an angle. Most of them are very high that are coming in from and/or going north from the bay, but once they come to land and head north they reduce altitude to about 20 or 30ft or so.
Which could mean that they're hopping between peninsulas over the water rather than following the dune line. Then once the Delaware water gap is thin enough further north they cross the bay (maybe when they start to detect less salt in the air or when they can see the shoreline across the bay). No evident storm, or anything coming from the south to influence them north.

Editor’s note: contacted observer for more information about this sighting.

During northwest winds or any north component they typically are pushed against the coast and south. The peninsula of Cape May County acts as a funnel for these migrating monarchs and the majority of the monarchs end up being concentrated at Cape May Point. However, monarchs don’t like to cross the Delaware Bay so move north along the Delaware side of the CMC peninsula to a point where the Delaware water gap is not as broad and possibly where they don’t detect as much salinity. Then they’ll cross at that point as far as we know. So that’s why they were headed north. On this particular day there were an abnormal amount of monarchs moving north than usual. None were nectaring in the grounds at the East Point Lighthouse (which is also abnormal), they were all actively migrating. So it was more so the rate at which they were moving north that was significant. Most of the individuals you see around Cape May are feeding for the most part and the ones that do start to move north don’t seem to move quite at the rate and at the numbers by which were passing by East Point. The interesting aspect of it, is that while counting the incoming monarchs, the incoming individuals were coming from off the bay (from a southwest direction which makes sense since it was northeast winds. They were going against the winds for uplift) to the point of the peninsula where the East Point Lighthouse is. Then once they reached the lighthouse and thus the shore, they continued north along the beach. So my guess would be that these individuals coming in from off the bay were coming from another peninsula further south along the Delaware. So instead of riding the typical thermals from the dunes along the coast, they seem to possibly be hopping between the peninsulas that come out in various areas along the Delaware Bay coast of New Jersey. So they cross the water only when there’s a visible peninsula on the other side. I work for the Monarch Monitoring Project in Cape May and tag up at East Point on the weekends and can tell you that it was an interesting movement, as it was very constant (as I said an average of 1.4 monarchs per minute for an hour) and in good numbers.

Millville, NJ

Latitude: 39.2 Longitude: -75

Observed by: Jack
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