Greetings all,
This week I want to take us back - way back - in time, and talk about a monarch paper that appeared in the Journal of the Lepidopterists' Society back in 1952 - 64 years ago! The paper in question is viewable online at the journal website - link here. It is only a page or two in length, and an easy read. It was titled "MIGRATION OF THE MONARCH BUTTERFLY DURING THE WINTER". I've had this in my stack of papers on my desk for years, but I think this is another one of those little-known, but important pieces of monarch science history that folks should know about. I encourage everyone to read it. When you do read it, keep in mind that at that time, the location of the winter colonies in Mexico were not yet known, and from the text it seems the general thinking was that the monarchs simply kept migrating, or at least moving, year-round.
The paper was essentially a report of monarch sightings from a site in central Florida, that were made during one winter. The guy who wrote the article was a scientist (Geoffrey Beall, who was known for several other early papers on monarchs), and it seems that he wrote the paper based on some observations made by a naturalist couple, 'Mr. & Mrs. KARL HODGES' who lived in Indialantic, FL - see the map below - I googled it.
This naturalist couple had been observing monarchs moving along the coastline during the late fall - actually more like early winter, and then during the spring.
Here is a screenshot of the paper that shows their observations. This table was the main 'results' of the paper:
From looking at the table, there are a couple of things that are significant.
First, all of the monarchs they saw in December were heading south, even when the wind direction was not in their favor. This implies the monarchs were flying with a sense of purpose, and the fact that they were all seen flying in the same direction (south) implies a mass movement - in other words, these monarchs were in a 'migratory' state. This, combined with the fact that it was December (well past the typical fall migration timeframe of Aug-Oct), plus the location of this site in central Florida means these were probably fall migratory monarchs from the northeast (or somewhere north) that had followed the Atlantic coastline southward and kept flying until they wandered into Florida, and from there, who knows.
This was back in the 1950s when we didn't know much. We now know that this happens every year, where some monarchs migrate along the Atlantic coast and they never seem to make it to Mexico. Records from multiple tagging studies done in coastal locations confirm this - we know that Atlantic coastal migrants have an extremely low tag recovery rate in Mexico (it's not zero though). And, we know from chemical analyses of monarchs in south Florida that some of them definitely came from northern regions. So all of the science we know, including these early observations, indicates that a non-trivial number of monarchs migrate into Florida for the winter - either by accident or on purpose. Actually, on this last point, there was a scientific debate many years ago (1979, I think) on this question, between Fred Urquhart and Lincoln Brower. Urquhart had seen this 'Atlantic' migration flyway from his tagging studies, and since the monarchs didn't seem to end up in Mexico, he called this an "aberrant migration". Dr. Brower debated this at the time, and on this one, I think I side with Lincoln. My take on it is, how can it be a mistake (on the part of the monarchs) if it happens every year?
So the fact the some monarchs fly to Florida each fall is actually less interesting than the other thing this table tells us, which comes from the Hodges' sightings of monarchs in March and April. This time of year is prime spring migration time, and by now most of the Mexico monarchs are just returning into the southern United States. Interestingly, the Hodges sightings in Florida all pointed to a northward flight, as if the monarchs there were also making a return trip! This is fascinating because this is an issue where we have little scientific evidence for. We know monarchs migrate into Florida, as I said above, but it's usually assumed that they then get 'trapped' when the reach the southern tip, and since it is so warm there, and there is lots of milkweed year-round (all tropical!), they just integrate themselves into the year-round breeding population. In other words, they enter, but never exit Florida. At least, that's what we thought. These observations by the Hodges suggest there is a northward flight out of Florida in the spring - very cool.
OK, so aside from the scientific value of these observations, here is why this paper is so significant even today - because it is published in a scientific journal. Scientific journals essentially serve as long-term repositories for information (in this case, obsrevations of monarchs) that will be preserved for all time. Consider this - here we are, 64 years later, reading about the observations of these people, and we find that they are still valuable. If their keen obervations had never been published in a journal, what would have happened to them (the observations)? They likely would have died with them (I'm assuming the couple has passed), and the rest of us would not know what they witnessed.
The lesson here is this: that monarch enthusiasts should make every effort to take careful notes of what they see, and to try to get their observations preserved in some way in a publically-accessable format. Doing so will ensure that these observations will be of use to scientists and will add to the collective knowledge about monarch biology. I can think of two possible ways to make this happen - one is to do what the Hodges did, and partner with a scientist to put the information in a scientific journal. Another way to preserve observations is to participate in some of the many citizen science programs, like Journey North, where such information is stored online, although this option is a little more tricky because the observations can become buried amongst the thousands of other records.
Either way you do it, you'll be helping the monarchs.
That's all for this week.