So last post was talking about a visit from October 2nd last year. Over the next several days, we made quite a few more trips to check on the lizards, and we kept finding more! Here are a few pictures:
The whole group sees a lizard!
The whole survey crew from Harvard, Boston University, and UMass Boston. Photo: Joe Martinez
All in all we’ve found over a dozen animals, pretty well spread out through the whole garden! What’s more, there were juveniles too so we know they’re successfully breeding. While no one can remember if they’ve been there for more than a year, it seems highly unlikely that they managed to spread so far afield and successfully reproduce just in 2016. My guess is that 2016 was their second year in Boston and they survived the relatively mild 2015-2016 winter by hunkering down in the garden’s many warm compost piles.
As to how they got there, now that’s a bigger mystery. The Connecticut and Hastings-On-Hudson populations we’ve previously discovered had railroad tracks right alongside them so the conduit for their northward expansion seemed pretty clear.
Just to remind you, here’s a figure showing the Greenwich lizards (magenta dots) and the Hastings lizards (green square) and both are directly on major railroad lines.
The Boston case is less clear cut. Yes, there are lots of railway lines connecting Boston to New York via southern Connecticut, but that’s a long scamper and we haven’t been hearing about sightings in between. It’s entirely possible a lizard hitched a ride on the undercarriage of a train, but for them to then scamper from South Station in Boston to the Fens (walking directions, google doesn’t have an as-the-lizards-run choice) seems like a long shot to me.
I have two more probable ideas, one is that the lizards hitched a ride with someone who grabbed them as potential pets and then released them into the garden when they got tired of feeding them. This is entirely plausible and is the cause of a lot of species introductions all around the world. Another option that I’m excited to test is that the lizards hitched a ride on some compost or mulch that was brought to the Gardens at some point in 2015. Lizard eggs move with plants and mulch all the time, even lucky adults could have made the trip without getting squashed or tumbled. One of my goals for this summer is to track down shipments coming into the garden to see if any might originate from sites with lizards. I’ll be sure to report back!
Another next step is to actually do some genetics work to try to figure out whether this population is related to the other Podarcis already in North America or if it could be a new introduction from the homeland. Those analyses are under way… I’ll report back as soon as we have an answer!
What is clear though is that the Italian Wall Lizard has made itself very comfortable in the Fenway Victory Gardens. Lizards were active all the way into the third week of November! Looking outside though we’ve just had another major snowfall, in amidst a week or two of serious cold snap, so we’ll just have to see if the lizards pop back up in a few months once we hit spring!
As they say down at the railway though, if you see something say something! As always, email me with tips if you see a flash of green in your garden or park!