Many gardeners have an appreciation for backyard songbirds. It’s a natural fit. As gardeners, we do a lot to invite them into our landscapes with food and shelter. All the more reason it’s concerning to know that many bird species are rapidly falling in their numbers, some at alarming rates. It’s time we all learn more about bird population decline and what gardeners can do to help.
Our guest for this podcast is the perfect person to explain what’s happening, and how we can help create sustainable habitats. John Marzluff, Ph.D. is a Professor of Wildlife Science at the University of Washington and author of several books based on his study of birds.
Dr. John Marzluff on one of his many bird study expeditions. (photo: Courtesy of John Marzluff)
His most recent book, Welcome to Subirdia, addresses tangible ways that we can successfully share our neighborhoods with wrens, robins, woodpeckers and other wildlife.
Ironically, the very day before this conversation, a study on bird population decline was released in Science Magazine, a highly-respected publication. Over the 50-year study, the rate of decline was staggering even to ornithologists. Nearly 30% of North America’s total bird population (3 billion) has been lost. It’s also considered a very conservative estimate.
The ripple effect of such a dramatic decline is far-reaching in its potential impact on food webs and other ecosystems. Just imagine – about 90% of a bird’s diet consists of insects. That’s a lot of bugs and a very effective method for keeping their populations in check. Take away 30% of the birds and we’ve got real problems. Birds are also critical in the dispersal of seeds and even help with pollination.
It’s a clear sign the system is not in good health and a vivid call to action that we all need to take action by doing whatever we can to halt the decline and turn it around to the extent that we can.
Reasons cited for this massive decline include changing agricultural practices and intensification of agriculture across the world. Endless acres of mono-crops such as industrial corn and soybeans are a major contributor. Add to that the increased use of pesticides and the conversion of remaining grass and pasture land and native prairie to cropland.
Pesticides are still a widespread problem in both industrial agriculture and home gardens in reducing insect populations birds rely on as a major food source.
Along with the gloomy outlook, there are a few kernels of good news. Overall, wetland bird species have increased their populations significantly over the same time. Why? Efforts by conservationists, special interest groups such as duck hunters with an interest in promoting habitats, and environmental laws have all played a role.
Raptors were another group of birds making a comeback – at least in part. But not surprising when you think about the fact that a lot of that has to do with the decline of certain pesticides such as DDT. What we’re seeing is really just a rebound of their populations. Only time will tell to see if those numbers hold.
That said, in the midwest, some of the raptors like Northern Harriers, (a grassland raptor) and Swainson’s Hawks, are declining for the same reason that some of the other grassland birds are.
The Inspiration for Subirdia
According to John, writing Subirdia stemmed from a facet of urban ecology that for far too long, was mostly ignored by ecologists. Urban and suburban areas were mostly written off as not being of much use to conservation. But John says that’s changed in the last several decades. The results of his observations of many bird species adaptation to subdivision sprawl led to his book and title.
John and his colleagues at the university which included urban planners, geographers, and ecologists started looking at our urban system in more detail, trying to understand how it affected a variety of human and natural systems and the connections they shared. John’s part of that study was to observe the birds that live around the Seattle area and how they were being impacted by changing habitats.
The areas of study included large, high stature forests that were being cut down and planted with the things we like around our homes. One of the biggest surprises was in how the bird communities changed in the face of declining forests and expanding subdivisions.
The natural expectation was for an overall decline in the bird population. To be sure, some birds definitely did decline. Notable losses included the true forest dwellers as well as prairie birds. So when forest and grasslands go away, so do the birds that depend on those environments.
The birds impacted by declines in their primary habitat are referred to as avoiders of human activity, in this case, suburbanization. That said, studies in Seattle and elsewhere show that the total diversity of species increases when in the midst of suburban sprawl.
The belief is that when you bring a lot of different habitats in close proximity including golf courses, yards, and landscapes while keeping some forest or prairie remnants, you have this diverse mixture of habitats, each supporting different groups of birds. When you total all those little pieces up, you get a higher number of species.
A diversity of plants including natives and ornamentals that offer value to birds can have a positive impact on their adapting to rapid changes.
But this is not equal across the board. We really have a complete shift in the community of many bird species that live around us versus those that live in more natural areas. Some birds exploit the opportunity by coming into our yards and using our feeders and the edges we create. In may cases, the net effect is an increase in the number of bird habitats and a higher diversity of bird species created in developed areas. John refers to this group of bird species as adapters.
Birds that exploit their human influence (think pigeons and crows) really do well around us. They actually have their best success being close to human habitation.
In other instances, the changes were too much and led to dramatic reductions. Imagine going from expansive forests to endless lawns in a couple of years. That’s very detrimental to some species. Winter wrens were an example of such birds that do not adapt well to sudden changes like this.
Actionable Steps We Can Take
If you’re concerned with bird population decline and want to know what you as a gardener can do to help, start by creating a more inviting and sustainable habitat for birds. Here are a few steps you can take that will make a difference.
Increase the habitat quality in your yard. The diversity of plants is key to better habitats. Focus on native plants, not just ornamentals, or at least choose ornamentals that are producing food berries or nectar.
Native plants are the best option for providing natural food sources birds depend on. (photo: Courtesy of John Marzluff)
Reduce the lawn. Grass doesn’t provide any fulltime benefit for birds. Consider replacing grass with plants and trees that provide more ecological function for the birds that provide food, shelter and nesting sites.
For the lawn you have, consider making part of it a “freedom lawn”. The term originated from a Yale study that included information related to letting your lawn assume a more natural, less mowed appearance. When you can get away with it (as John has done in part of his backyard), the results are amazing for what is attracted to this naturalized environment. For John, he’s noticed a remarkable increase in the bees, birds, and insect activity. Even salamanders have increased their numbers now that the non-disturbed area stays moist.
We discussed this concept in an episode of Growing a Greener World®. Garden writer and author Margaret Roach showcased a beautiful and lively example of this in her 2.3 acre upstate New York garden landscape.
Focus on structure and layers. Birds favor certain layers of your landscape, from the highest canopy trees, understory trees beneath, shrubs, perennials, and groundcovers. By including all layers in your landscape, you provide the greatest diversity of habitat for a wide variety of bird species.
A well-structured landscape consisting of various layers including canopy and understory trees, shrubs, perennials and groundcovers offers many options for attracting a variety of bird species
Growing a Greener World also has a good example of this layering concept in this episode featuring Rick Darke and Doug Tallamy in our episode on Bringing Nature Home.
Focus on attracting native birds. It’s important to know what birds are there, and what effect they have on the ecosystem. If you’re just feeding non-native birds like starlings and house sparrows, then it really isn’t doing any good. While it’s maintaining those species, they might be using resources that native species could use better. And so again, if your first strategy is to diversify your plantings, you’re going to be helping native birds.
Provide food and nest boxes. In most cases, especially here in the United States, providing nesting boxes and supplemental food sources is beneficial. It increases the health of the birds that are eating those foods and it increases their survivorship during the winter and even during the breeding season. That’s very important because it translates into larger populations of those species that can live with us and that do utilize the food we provide.
Don’t light the night sky. A lot of our migratory birds do so at night. If the sky is lit, they may be attracted or disoriented by those lights and oftentimes that cause them to crash into structures nearby. Mortality is increased by the lights that we put out at night, especially during the spring and autumn migration periods.
Even small ornamental and house lights that are increasingly popular now cast a broad swath of light. The problem is that many birds that hunt at night rely on that darkness as their cover. With outdoor lighting, that’s taken away from them and species decline because of that.
Avoid the use of pesticides and herbicides. If we’re killing insects with non-selective pesticides, we’re taking out a vital food source that birds depend on. Even though we might provide feeders with seeds or even mealworms and other bugs, that’s no substitute for the blooms of insects that most of our birds have come to rely upon.
Birds have evolved to time their breeding when insects are abundant to feed their young that high protein, high-fat diet that that a young growing bird needs. The more pesticides we apply to reduce those insects is directly detrimental to bird populations.
Herbicides that kill weeds also eliminate their seed production. Think of thistle and dandelions. Goldfinches and many birds rely upon these and other seeds as a primary food source.
Keep cats inside. It is estimated that three to four billion birds die each year by cats. It’s the number one cause of bird mortality. Keeping cats inside is the number one thing we can all do to increase the sustainability of birds in our yards. Another effective but under-utilized option is to use a leash when giving cats some time outdoors.
Although not often used, a good compromise for keeping birds safe while giving cats some outdoor time is to use a leash. (photo: Courtesy of John Marzluff)
Take precautions to avoid birds flying into windows. Window strikes are the second most common cause of bird mortality. According to Margaret Roach from this episode of Growing a Greener World on Gardening for Birds, feeders should be within three feet or more than 30-feet from windows to minimize the risk of bird strikes.
Other options to reduce strike risks include stretching bird netting tightly across the exterior side of the window to serve as a cushion when birds fly towards the window. Another option is to use ultraviolet reflective stickers and tape. These products are nearly invisible to humans yet birds see them as a solid, non-transparent area and fly clear of the glass.
Hopefully, by now you’ve had a chance to listen to this fascinating conversation. If not, you can simply head back up to the top of this post and click the arrow in the green play bar to listen now. You can also subscribe to The joe gardener Show Podcast wherever you consume podcasts. We’re a weekly show with new episodes posting every Thursday.
Links & Resources
Episode 012: Bring Nature Home with Doug Tallamy
Episode 077: The Beauty and Importance of Native Plants: The Ethos of Mt. Cuba Center
joegardener Online Academy: Master Pests, Diseases, and Weeds – Just $47 for lifetime access! Watch for my new course on seed starting coming soon!
GGW Episode 418: Gardening With Margaret Roach
GGW Episode 526: Backyard Birds With Margaret Roach
GGW Episode 620: Bringing Nature Home with Doug Tallamy and Rick Darke
GGW Episode 906: Mt. Cuba Center: A Native Plant Public Garden Like None Other
GGW Episode 907: New York’s High Line: A Thriving Diversity of Plants and People
Welcome to Subirdia by John Marzluff
John Marzloff’s TED Talk: Crows Are Smarter Than You Think
Science Article: Three Billion Birds…
Rainbird: Podcast episode sponsor and Brand Partner of joegardener.com
*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
0 Responses to “134-Bird Population Decline and What Gardeners Can Do to Help”
Joe, it is kind of interesting how all of us who love to garden love to feed and watch birds as well. My neighbors and friends that garden all have bird feeders.I can’t whistle though so I guess I won’t ever qualify as a true “Bird Watcher”. I think I will break up my observations into a couple separate comments this time. I know that I get carried away some times, but me and all of the other Joe gardeners appreciate your replies. Frankly I don’t know how you keep up my friend.In the winter of 2018 there were four dozen or more of american gold finches at a time at my finch feeder. It got to be where I would scatter additional feed on the ground for them because there wasn’t enough room on the tube feeder for all of them. I kept it in a separate location from the other feeders. In the winter of 2019 – not a single one. The tube feeder sat there full with other birds getting what fell into the tray. And occasionally the deer would knock it off the shepherds hook and roll it around. But the feeder didn’t go down all season.Also absent in the winter of 2019 were the big flock of blue jays that we were accustomed to having on a regular basis. They are one of my favorites, the way they take turns coming in and out to hoard and keep watch for one another. The dove visitors were on the increase. The other species seemed to be about normal in numbers. I will let you know if the finches are back in 2020.Joe that was great information and tips from John. One thing, I have had some bad experiences with birds getting caught and injured in bird netting, so I don’t use it anymore. I would suggest vinyl window screening in place of netting.Regards
Forrest
Nanty Glo, Pa.
Hello fellow bird lover.
This is very interesting about the ebbs and flows of certain species, such as gold finch and blue jays. I have noticed that with other birds, such as rose breasted grosbeak (one of my very favorites). They are a rare sighting here in my N. Atlanta garden but I get so excited when one comes to visit my feed for a few days. And then, woosh – they’re gone for a few years before I see another one.
I will say I had a plethora of gold finches. They were feasting on the seedheads of my coneflower. I loved watching them every day. I’m always so fascinated when they just show up because they find them. How they do that I will always be in awe.
Blue jays have been abundant here this year after a few years of being very scarce. Always a mystery. I’ll just keep doing my part to keep them safe and fed.
And by the way, I agree with the bird netting. I opted not to use that over my windows.
Thanks for checking in Forrest.
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Yes, the tube feeder was full of finches so I put feed on the ground and top of post. We really enjoyed seeing them in 2018. I am right there with you on the grosbeaks Joe. After having never seen them here before, a handful of pairs showed up about 4 years ago. They have come back again each May and leave in late July. It looks like they are just passing by you on their migration route Joe but they go a little more north for the summer to breed. Yes I am a fellow bird lover. I do need to learn how to ID more species though.
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