A faithful male Rose-breasted Grosbeak takes his turn on the nest at Bear Creek Nature Park.

On March 21, Dr. Ben VanderWeide, the township’s Natural Areas Stewardship Manager, shared a Cornell Lab of Ornithology presentation on how to safely and accurately monitor bird nests as citizen scientists. Cornell Lab and other researchers count on citizen scientists to provide important information on the nesting success of common birds in our backyards and our parks. If you’re intrigued by this introductory information, there’s a lot more available at www.Nestwatch.org. It’s an amazing resource, as you’ll see by all of the links below!

First, the Rules of the Road

The Eastern Kingbird looked proud of her handiwork once she finished her nest.

Cornell’s Nestwatch has an official “Code of Conduct” for nest monitors to ensure that the data is collected while protecting native birds, their nests, eggs, and young. It’s important that monitoring doesn’t attract predators and that parent birds don’t desert the nest.

• Please don’t touch the nest, the birds or the eggs when checking nests or nest boxes!  Migratory Birds are protected by the Migratory Bird Treaty Act.  They cannot be harassed or harmed.  The only exceptions are those of aggressive invasive bird species like House Sparrows (Passer domesticus) and European Starlings (Sturnus vulgaris) that are not from North America.  (See more info on predators below.)
• Don’t check nests in the early morning, which is when birds typically lay their eggs.  If the female leaves the nest during monitoring, the eggs may become too cool.  Afternoons are best for monitoring.
• Avoid nests during the first few days of incubation. Only approach if the parent bird has left the nest.
• If monitoring a nest box, tap softly on the box to allow the female to leave if she’s present. Or try singing or talking softly as you approach the nest.
• Don’t approach nests when baby birds are close to fledging so they won’t try to leave the nest before they are ready. Once young birds are alert and fully fledged, only observe from a distance.
• Avoid monitoring nests in bad weather like cold, rain, etc., when birds need the nest or nest box for protection
• Don’t check nests at dusk or after dusk when females may be returning. Again, afternoons are best. The exceptions, of course, are owls who leave their nests at night.
• Approach and leave the nest site from different directions at each visit so that you don’t create a path for predators like cats, raccoons, etc.
• More details about the “Code of Conduct” at this link

Collecting and Recording What We Learn

A Cedar Waxwing nestling

• Visits to the nest should be no longer than a minute. Take a quick look and jot notes at a distance. Use binoculars for more distant cup nests.
• Check the nest every 3 or 4 days. Checking more often risks disturbing the nest; less often makes the information less useful.
• Record when the first egg was laid. Birds normally lay only one egg per day, so the number of eggs tells you when she laid her first one. Easy, eh?
• Record the number of eggs and any interesting bird behavior. (Cornell provides data sheets for this.)
• Record your data at Nestwatch.org. If you’re working on backyard birds, start an account and you’ll be provided with an online form for entering your data. If you want to volunteer to monitor in our parks or along the Paint Creek Trail, please join our Oakland Township Parks NestWatch Chapter by contacting Dr. Ben at bvanderweide@oaklandtownship.org or call the office at 248-651-7810. You’ll need to take a brief quiz after reading the Code of Conduct material at Cornell in order to be a certified bird monitor.
• More details on collecting data at this link.

Finding Nests in Our Backyards

A male Yellow Warbler holds a bright green caterpillar for his mate at Bear Creek

• Check out information on typical nest locations and materials for the birds in your yard by going to http://www.allaboutbirds.org. or a bird/nest field guide.
• Watch where males are singing to establish their territories or listen for females who sometimes sing from the nest.
• Watch for birds carrying nesting material like moss, twigs or grass.
• Watch for birds carrying food, like caterpillars or worms, to feed the young.
• Listen for frantic calls of young birds begging to be fed.
• Check out areas where you’ve seen nests previous years. Though birds seldom reuse the same nest, they often nest in the same area.
• More details  on finding nests here.

Setting Up and Monitoring Nest Boxes

A male Eastern Bluebird guarding his nest box.

Dr. Ben and Tom Korb are trying two different kind of Eastern Bluebird (Sialia sialis) boxes in the township – the traditional ones seen above, and Petersen boxes (see left) which have a more triangular shape.

A Peterson bluebird box

We’ll learn which style our bluebirds prefer. They’ve paired the two types bluebird boxes to see which box design our local bluebirds prefer. Paired nest boxes may also help with competition from Tree Swallows. Others have found that if Tree Swallows (Tachycineta bicolor) occupy one box, they will live peaceably with bluebirds next door. We’ve also installed American Kestrel (Falco sparverius) boxes and a box for smaller birds such as chickadees, nuthatches, or Prothonotary Warblers (Protonotaria citrea).

For details on building/buying nest boxes for your back yard, check out this helpful page on nest boxes at  Nestwatch. For more detailed plans on bluebirds and their houses, check out the website of the North American Bluebird Society or this link at Sialis.org. Nestwatch even shows you the right house for the birds in our geographic area.

Beware of Predators!

Predators can approach native birds from the sky and the ground. (Click on photos to enlarge; hover cursor for captions.)

Ground Predators

Raccoons are native predators of bird eggs.

Native snakes like the Milk Snake eat birds eggs but need protection as a native species.

• Raccoons and outdoor or feral cats are major predators for birds. A well-respected, peer-reviewed study cited by Cornell found that as many as 1.3 to 3.3 billion birds are killed by cats each year in North America. They are skilled bird hunters! And raccoons can wipe out a whole group of nests in an evening!
• Keeping pet cats indoors is a great idea if at all possible.
• Make sure your nest box is at least 6 feet off the ground so raccoons and cats can’t jump on top of the box. If they do, they “fish” for eggs and chicks through the hole.
•  The right roof and predator guards on the bird house pole can make a big difference.
• Avoid leaving pet food or birdseed on the ground, which encourages predators.
• Keep your nest box away from overhanging trees to keep squirrels from dropping on them and chewing the holes to get in.
• Snakes can be deterred by locating nest boxes away from brush piles or by putting a metal collar/predator guard below the nest box on the pole.

Bird Predators

Invasive and aggressive House Sparrow (photo by dlbowls (CC BY-NC) at iNaturalist.org

Invasive European Starling

Aggressive, invasive birds, especially the House Sparrow and the European Starling, will attack and kill native birds, their eggs and their young to take over a nest box. Because they are non-native and plentiful, they are not protected by the Migratory Bird Treaty Act.  So how to deal with these predatory characters?

• If you don’t want to deter invasive birds, please  consider not putting up bird boxes. These invasive birds are already abundant and  actively attack and kill our native species. Providing them with food and a nest merely exacerbates the problems for native birds.
• Choosing an appropriate entrance hole size on a nest box is important. Starlings can enter and attack American Kestrels in their boxes – but starlings are too large for a bluebird box if the entrance hole is the right size. House Sparrows, however,  can easily attack bluebird boxes. NestWatch has more information on passive and active means of deterring these non-native predators – from changing nest location to removing nests and eggs or trapping adult birds.
• Be sure you know what Starlings look like and are able to distinguish House Sparrows with their black triangular bibs from our many species of native sparrows.
•  These two invasive birds make messy nests with bits of plastic, cigarette butts, paper, etc. so distinguishing them from native nests is easier once you are informed about the appearance of your native bird’s nest.
• Native birds, like House Wrens (Troglodytes aedon),  occasionally attack other birds to take over a nest as well. And native Brown-headed Cowbirds (Molothrus ater) lay their eggs in the nests of other birds. Because these birds are naturally occurring species in our area, they are protected by the Migratory Bird Act and should not be removed or harmed.
• Bees, wasps, squirrels and mice can inhabit nest boxes at various times of the year. Nestwatch has info on coping with them, too.

So Why Become  a Nest Monitor?

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Helping our native birds raise their young in safety is crucial to slow the declining numbers of many bird species. Bluebirds, for example, were threatened until citizens began a campaign of installing and monitoring bird boxes for these azure beauties. The data from nest monitors since NestWatch began in 1965 has provided vital information on over 600 species and resulted in 133 scientific articles and 9 ongoing studies. With the data the public collects, researchers can detect  shifts in bird populations related to landscape and climate change. Saving native birds is important to preserving the beauty of our local natural history.

But beyond all that, c’mon!  What’s more delightful than baby birds? Being a friend to native birds is always good for us, as well as for our feathered friends.