Build it and they will come

“Build it and they will come” has been the underlying philosophy for our restoration work to support the dwindling populations of coastal cactus wren, a species of special concern in Southern California.

Since the Witch Creek Fire swept through parts of San Diego County (including parts of the Biodiversity Reserve at the San Diego Zoo Safari Park) in October of 2007, ICR staff have been building new habitat by planting cactus to support the north county population. Over the past several years, some 6,000+ cactus have been planted by ICR at the Safari Park and nearby Lake Hodges. But to be honest, we couldn’t be sure that we were doing was going to work. We could just do our best to provide good habitat and hope the birds would find their way.

And… they have!

While out with one of our summer fellows documenting cactus for her project, we checked out an area of cactus planted in December of 2010 as part of an experiment (which meant they had tags dug in next to them and we knew for sure when they were planted!). After gingerly reaching between some cactus arms to read a tag, I was surprised to look up and find a nice little cactus wren nest just above me!

Coastal cactus wren nests are unusual, football shaped instead of the open-top nests people usually think of for birds. Covered with downy grey feathers, the entrance to the nest we found had clearly been in use this past breeding season. I quickly snapped a photo and texted it to my former coworkers who had organized the cactus planting in 2010 (and personally planted countless cactus pads). They were ecstatic to see their efforts pay off – even if I had absentmindedly texted to tell them before 7 in the morning!

Ecological restoration is not a field for the impatient. Some processes, like growing cactus, just happen slowly. This can make it extremely difficult to know if your conservation actions are actually helping.

For this project, we monitored cactus survival and growth for the first couple of years (when they’re the most vulnerable), but couldn’t really spend the time or staff time to track the cactus for the seven years it was estimated to take before the cactus reached the height suitable for wrens to build their nests. We were fortunate to have the summer fellow program help support a quick evaluation of some of our plantings this year.

In addition to retreading some of the areas with planted cactus, this past spring we also conducted some surveys for the birds to see if they’ve expanded their habitat. Results of that study are pending, but it is definitely encouraging to see a nest in an area that didn’t have one before.

The slow growth of cactus is a good reminder to take care of habitat when you can.

Restoration is hard and slow - and not always guaranteed to work. Our current projects at ICR to help coastal cactus wrens are focused on reducing weed cover to keep habitat already occupied by wrens from degrading. The 2007 fire helped proliferate a weed that grows very densely and reduces the bare ground between shrubs and cactus that wrens use for hunting insects. Such dense weeds are also often more susceptible to ignition and controlling them helps reduce fire risk.

We have built it and the wrens have come. But we still have work to do to ensure the coastal cactus wren has habitat for generations to come.




My third grade students

My name is Holli Joyal and I teach TK-5 Science at Tarbut v'Torah School in Irvine, CA. We have been doing a canned unit from a curriculum called Amplify that talks about habitats and endangered species, but I really think my third graders, who are pretty worldly for their ages, need something real to this area to work on. I have studied about the coastal cactus wren and wanted to see if you have any other information than that which is shared on your website or anyone who might be willing to facetime with us to talk about how our kids to try and design a virtual solution. I was thinking about a problem based activity where developers were looking to build a shopping mall in an area where there is a thriving cactus population, even further degrading the amount of cactus, thereby, creating more danger for the coastal cactus wren's survival. I am fighting an uphill battle as I only have the kids one day a week, but any help or nudge in the right direction would be spectacular.

Thanks for your time.
Holli Joyal

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