Birds do it. But you knew that. So do Monarch butterflies. And you probably knew that, too. But what you may not know is that many other species of butterflies, as well as moths and dragonflies, also do it — migrate, that is.
"On the East Coast, there are about 30 species of insects that are documented as migrating in sort of a north to south pattern in the spring and the fall, much like we think about birds," said Rhiannon Crain, director of the Habitat Network, an interactive citizen scientist project. One of the aspects of insect migrations that intrigues Crain the most is that insects that start out on these migrations are not the ones that return to the starting point.
"I think people still don't necessarily understand this," she said. What happens, she explained, is that the insects will mate on the first leg of the journey, and then the adults die. Their offspring, which start life as caterpillars in the case of butterflies, will form cocoons, leave the cocoon and continue the migration as adult butterflies. Continuing with the butterfly example, the second generation of butterflies will mate later in the journey and the process will repeat itself. "So, it's the great grandchildren of the original migrating adults that will show up back at the breeding grounds," Crain said.
There's another thing about insect migration that keeps it under the radar, said Crain. The insects travel at night, probably to avoid predators, so people typically don't see the migrations. When they do, the sight can be startling. "I have heard some anecdotal stories about runners alongside Lake Superior who have been confronted with clouds of dragonflies that were clearly on the move. So, there are instances where you will get these large, aggregate migrations. But I think it is a largely hidden phenomenon to most people."
The fly in the ointment for migrating insects, so to speak, is loss of habitat. An annual round trip for some of these multiple-generation, single-season migrations is up to 1,000 miles or more. Along their flyways, due in large part to habitat loss, host plants on which migrating insects lay their larvae — and on which the caterpillars that emerge from the larval stage will feed — are becoming more and more difficult for mating insects to find.
Some types of dragonflies migrate too, like this wandering glider. (Photo: John Flannery/flickr)
A new partnership
That's where the Habitat Network — and you! — come in.
The Habitat Network is a partnership between The Nature Conservancy and Cornell Lab of Ornithology and is housed at Cornell University in Ithaca, New York. The project launched at the Cornell Lab of Ornithology as Yardmap in March 2012 as a way for homeowners to use landscapes to attract birds to urban and suburban yards. Depending upon the enthusiasm of participants, Yardmap could also be used for the same purpose at their children's schools and even at the office parks where they work. In October 2016, the Cornell Lab of Ornithology and The Nature Conservancy formed a partnership that expanded the Yardmap platform into the Habitat Network. The goal of the expanded program is to attract wildlife in general, not just birds, to urban and suburban landscapes.
Importantly, insects are part of that wildlife. And, as a bonus, with insects you get birds.
"I think people think about birds as just eating seed," said Crain, pointing out that even birds that are seed eaters like chickadees, which are prevalent in most places in the country, hardly any eat seeds during breeding season. "When they are trying to raise nestlings, those nestlings require an enormous amount of protein. Some counts have said that a nesting pair of chickadees has to catch 8,000 caterpillars to successfully raise a nest of young." Without habitat that attracts insects that will produce caterpillars, Crain pointed out, homeowners won’t be able to support many types of birds, regardless of whether they are mating.
Most songbirds, for example, are complete insectivores. "All the warblers, all the beautiful little jewel birds that migrate down to Costa Rica and farther south during the winter … they don't really eat seeds at all. They rely on insects, and that's one of the things that's driving their migration, the lack of insects in the north during the cold months," explained Crain.
One of the goals of Habitat Network is to raise awareness of the insect migrations and the important role homeowners can play in creating way stations for them during their arduous journey. By creating insect-friendly habitats, homeowners will not only lend a helping hand that will aid the insects in their struggle to find food and survive but they will also improve their changes of attracting birds that feed on the caterpillars the insects leave behind.
Which is where you, the homeowner, come in.
How the Habitat Network works
Getting your yard ready for insects like this buckeye butterfly (and all that they bring with them) is an important step. (Photo: John Flannery/flickr)
"One thing we are really interested in is getting people to change their mindset about insects in their yard," said Crain, aware that many people might see holes in leaves as unsightly rather than a measure of success. "It's pretty easy with butterflies and moths to be friendly to those, and I think that's a good entry point for helping people to think like, 'Oh! I’ve got these insects that are migrating through and they are covering these vast distances and trying to eat and be safe from predators.' So, a yard can really support these migrations in pretty profound ways."
Habitat Network lets you customize your actions based on what you want to support — be that butterflies, dragonflies, birds or something else. The project will help you support your favorite type of migrating insect as well as insects in general. Once you've made that decision, scientists at the Habitat Network will work with you to help you decide what you to plant in your yard to attract your favorite genera.
Here's how you can help them do that:
1. Create an account. Go to the Habitat Network home page and find and click on the "Join the Habitat Network" button. Then just fill out the “Create an Account” form that will pop up. The account is free and will allow scientists to put your information into Cornell's secure citizen science database.
2. Access a Google satellite map of your house (or the area you are mapping). There are instructions, but this will be easy if you have ever searched for something on Google Maps before.
3. Select the tool that lets you outline the property you are stewarding. You are basically defining the space you are going to map with this outline. Think of it as a fence around your property, Crain suggested.
4. Fill in the outline. Start with shapes that represent the existing land cover. "You will trace out the edge of the lawn with a polygon and then that shows up on our end as a lawn polygon in our database," said Crain. Then you continue with a polygon for the buildings, the shrubby areas and any woodlands, ponds or other special landscape features you might be lucky enough to have. "Now you’ve got the shape of your property with colored polygons depicting the different kinds of land cover on your property," said Crain. "Once you've done that," she added, "you'll get a cool pie chart that will quickly show you … 'Wow! 28 percent of my home is lawn, 17 percent is building, 14 percent is in flowers and 3 percent is in vegetable garden!' It's kind of a fun thing to see just how your property breaks out."
5. Add wildlife-friendly objects. You'll also draw a polygon for wildlife friendly objects such as a bird feeder, a brush pile or, perhaps, a dead standing tree. You can even add something as simple as a log or something more complex such as solar panels. You can also add individual trees such as a big oak in your front yard that makes you really proud. "All these get logged into our database as part of your map," Crain said.
"At that point, with your yard mapped, you can use the planning tool. It will tell you how close, or far, you are from achieving your goals," Crain said. Habitat Network will even take this a step further. "We'll look at the map and analyze it and we'll say, 'Hey you said you were interested in attracting butterflies, dragonflies or amphibians and here are the things you are doing in your yard that are really good for those things based on what you mapped and here are the other things you should be doing if you really want to support your specific interests. Folks can then shuffle through our recommended lists of tasks and pick out ones they feel like they can or can't do. And, over time, you can come back and update your map with the changes you have made. We save those iterations. Then, sometime in the future, you can look at how your property has changed over time." One thing project participants should know about the feedback, sad Crain, is that "we don't get preachy."
Scientists at the Habitat Network measure success, yours and theirs, in several ways. One is just helping home owners "get it," that their yard can include plant communities that support wildlife in all its forms, from insects such as beetles that inhabit fallen logs to plants such as milkweed that provide food for migrating Monarch butterflies. "Whatever their goal might be," Crain said.
Another is just having a complete up-to-date yard map. "It means you've shared data with folks who are really interested in it,” said Crain.
"As a project, we will measure success as we start to set the data up robustly enough that we can start analyzing data with spatial ecologists," said Crain. That will allow us to try to understand by matching up this detailed landscape data with impacts it can have on wildlife. That will help us answer questions that people always have about what should I do with my yard. We have a lot of anecdotal evidence, but we don't know a ton about what actually should be done based on various specific locations."
Is it working?
Because the nature of the project is to compile data long-term, it's too early to reach definitive conclusions about what the project is accomplishing, Crain said. There are positive indications though that the Habitat Network is having a positive influence.
"Based on NASA satellite imagery of how much lawn people have, we've put together an infographic showing what we suspect is the average size of lawns in the United States," Crain said. The rough estimate which she said should be taken with a grain of salt, is that 60 percent of U.S. residential property is lawn, almost 20 percent is impervious areas such as driveways and buildings and just a small amount is devoted to more complicated vegetation such as flowers or shrubs, the kinds of things birds and insects need and use.
"I pulled all of the data from Habitat Network to see what is going on with people participating in the project (25,000-plus sites and more than 447,000 acres mapped) to get an idea of whether people using Habitat Network have lawns that are larger or smaller than average," Crain said. What she found is that the average size lawn of someone who is in Habitat Network is about half of average-sized American lawns. "I think that's kind of cool," she said, though she added that she doesn't know if the project attracts people who have already embraced the concept of small lawns or if project participants reduced their lawn size after creating a Habitat Network account.
Amount of lawn needs vary depending on individual situations. Whether you have kids who want to use it for play of you have an acre to mow. One option for a big lawn, she said, is to turn it into a meadow.
As a guideline for lawn size, Crain pointed out that one metric some municipalities use to issue new landscaping permits is to require that lawns be less than 25 percent of the landscaping. "We say you have a small lawn when you hit that 25 percent threshold as well. That would be a pretty small lawn, and hitting that 25 percent would be pretty great."
If the vision of Habitat Network has you enthused but you're wondering where you can find plant material to attract your favorite migrating insects or other wildlife, don't worry. Habitat Network scientists have an answer for that, too.
"One of the inhibiting factors of landscaping yards for wildlife is not being about to find things that apply to people locally," Crain said. Habitat Network's solution for this problem was to create a tool called the local resources tool. "This tool takes zip codes and provides a list of pollinator-friendly plants that are native to your region and shows you all the birds recorded around you in the last 30 days so that you will know exactly what kinds of plants you should be planting to support pollinators. We also will hook you up with your local Cooperative Extension office." If you have a question specific to your exact county or region, an Extension agent can help you with questions about pests or other problems that impact gardening, such as getting your soil tests. The tool will also provide a list of plant sources near you, including nurseries that specialize in native plants.
"Habitat Network is a community of people who care about changing the way their yards look and function," Crain said. The community communicates though social networking forums based inside the tool and on Facebook, Twitter and an e-news channel. "If you care about how your yard looks and attracting migrating insects and other wildlife, this might be a good resource for you."