Sarah Hedean is the Living Collections Manager at Smithsonian Gardens. I sat down to talk with her on August 9, 2017 about bluebird nesting boxes at the Smithsonian Gardens greenhouses. For part one of our interview, on the subject of her career, the field of horticulture and some of her current undertakings with Smithsonian Gardens, see Horticulture is Hard Work, But Rewards Bounty and Beauty.

How did you come to do the bluebird nesting box project?

When I was in graduate school I actually lived at Longwood Gardens. I was the only person who lived inside the gardens. I got to live inside the gardens because I managed all the student housing. My apartment looked over the meadow. Outside my window I could see the bluebird houses. They have I think in their program 150 bluebird boxes throughout all the outer garden areas. The meadow is one of those areas where they have a lot of bluebird houses.

When [Smithsonian Gardens greenhouses] moved to our Suitland location in 2010, it previously was a 10-acre wooded lot. A lot of that was razed to put the 10-acre greenhouse facility in, and there’s the buffer areas that are still wooded. We noticed the first year we were there that there were a lot of bluebirds. There were bluebirds on the fence. We saw bluebirds in the trees. We saw bluebirds just everywhere. And I hadn’t seen bluebirds since I moved to Virginia from Pennsylvania. I’d seen bluebirds all over Pennsylvania. I contacted my friend at Longwood [Gardens] and he put me in touch with one of their long-term volunteers, Richard Gies, and he had been working with the program I think for thirty years.

I had been to Longwood for something else, prior to us moving to Suitland, and I had seen these boxes along the road and was noticing that they were paired. I was also noticing that they had green roofs on them. There are all these succulents coming off them. There was one day when I was visiting my friend Casey and his family, and I actually pulled off the road. I was so excited to see these paired boxes right next to the road, and they had these beautiful sedum. I’d never seen that. I stopped and took a picture. And I kind of put two and two together. I thought we have these bluebirds, we have a brand-new facility. What if we thought about why they are pairing these two boxes together? What’s that about? Why do they have the green roofs??

Richard came [to the greenhouses] for the day. He walked around the property. He identified the areas that would be best for bluebird houses. We also had tree swallows and tree swallows are a very aggressive species. Both are cavity nesters, they both are fighting for the box. They’re about the same size so the hole can accommodate them. Because the bluebirds are so shy, if there’s only one box, the tree swallow’s always going to win out. But if you pair the two boxes together they can live simultaneously. The swallow will take one box and the bluebird will take the other box and they won’t compete. But they were having this problem at Longwood, that the bluebirds were losing their habitat because these other birds were more aggressive. And because they were so much more aggressive they were reproducing at a much faster rate and the bluebirds were getting pushed out. They thought what if we pair the boxes? And they had five years of data that was supporting that pairing the boxes brought both populations together and both populations were increasing in size.

The green roof keeps the box cooler by eight degrees in the summer. If the birds are nesting through July, and it’s really hot, then they won’t get cooked in the box, which can happen if you have a really hot summer. So we contracted with Richard, and he built us the twelve houses and we put ten at the greenhouse and there’s two more to put somewhere on the Mall. But on the Mall there aren’t any bluebirds because it’s an urban setting and they’re shy birds and they don’t like urban areas. They like open areas with a wooded tree line. We had that perfect environment in Suitland but not here downtown.

That’s how we got the bluebird project going and it’s been really successful. We probably have about four to six broods a season, which is a lot for ten houses. And they tend to pick the same houses. They have their favorites and the ones we thought would be their favorites haven’t been the favorites. It’s been a really interesting learning experience. We’re also getting wrens, we’re getting tree swallows, we’re getting robins not in the boxes. Robins are nesting in the cymbidiums that are outside for the summer. There are birds everywhere.

It’s been nice for us to think about our environment and our being a habitat within that space. Our plan for out there is now to start planting winter berries that the birds can be eating to help also support the population.

For more about how Smithsonian Gardens created its Eastern Bluebird Habitat Trail see the blog Smithsonian Gardens Greenhouses Welcome Bluebirds.

Learn how to create your own green roof Eastern bluebird nesting box designed by Richard Gies for Longwood Gardens.

Interviewed by Nicole R., Smithsonian Gardens volunteer August 9, 2017.