Finding a cardinal nest
Ihad hoped to find an active bird nest this year to monitor. It turned out I didn’t have to go far. On June 26, a male northern cardinal landed on a short shepherd's hook holding a ship’s-bell wind chime in my yard. I can see the hook from my bedroom and often watch the pair of phoebes that claim it every year as a vantage point to hunt insect prey on the ground. The pair, like me, were surprised to see the cardinal’s usurping it.
I was even more surprised when the cardinal’s mate joined him. Holding long pieces of dried grass in her beak, she quickly took off toward the wild hydrangea I’d planted at the edge of an old vegetable garden that is being converted into a native meadow garden. Knowing cardinals use grass to line their nests, I looked to see where she had gone. The male soon headed in that direction as well. The shrub had grown in the last few years to spread out and up to about 6 feet and fits cardinals’ usual criteria.
Cardinals inhabit a variety of places, as Peterson’s “A Field Guide to Birds’ Nests” notes: “thickets, forest edges, groves, suburban gardens, parks” and (my favorite) “deep forests typically shunned” (by what, the guide does not say). Within these habitats, they place their nests four to five feet up in dense shrubs, vines, briars or other thick growth that obscures it and deters predators from finding and accessing it. Like the eastern phoebe, Carolina wren and a few other songbirds, this species often will nest close to houses and is relatively tolerant of people. A few years ago, I had found a cardinal nest with three eggs in it in a honeysuckle-covered bush a few feet into the forest edge at the back of the yard, writing about it in my April 25, 2013 column.
A cardinal nest has four layers. The first consists of coarse, loose stalks of weeds and vines (sometimes with bits of trash added), which are then covered by a layer of leaves or papers and grapevine bark. The third layer consists of fine weed stems, grass and trailing vines. The last layer, the lining, consists of grasses, stems, rootlets, pine needles and hair.
While cardinal males may provide some nest material, the female does most of the construction. According to Cornell Lab of Ornithology’s All About Birds website (allaboutbirds.org), she takes the coarser materials and crushes them with her beak until they’re pliable, then turns in the nest to bend them around her body, pushing them into a cup shape with her feet. The finished product is about 3 inches tall and 5 inches across, with the inside of the nest about 3 inches wide and 1.5 inches deep. The female builds the nest in three to nine days but may wait almost before she starting to lay eggs in it.
Cardinals build a new nest for each clutch of eggs and usually have one or two clutches of eggs a year in Virginia but can have up to four. Being a year-round resident, this species starts reproducing early, in March, getting a jump on some other songbird species for good nesting sites. Not having to prepare for migration in the fall, cardinals can also continue reproducing into September.
Clutches range from two to five eggs, with three the most common number. The female lays one egg each day until the clutch is complete. The eggs are oval and an inch long. Like the nest, they are well camouflaged by their mottled color: white, sometimes tinged with blue, gray or green, densely or sparsely covered with brown (sometimes gray or purple) blotches or spots.
Only the female incubates the eggs, for 12-14 days. The male brings her food and keeps watch for predators; sometimes she leaves the nest and joins the male to be fed by him. After the eggs hatch, the female broods the chicks for five days, with the length per day diminishing over that time. While she’s brooding, the male brings her and the nestlings food; once she quits brooding, both parents feed the young.
The chicks fledge in nine to 11 days but can’t fly the first day or so after fledging and sit perched near the nest. The newly fledged young continue to demand food from the parents, both of which comply except when the female is starting another brood, in which case the male alone has feeding duty.
As with humans and many other species, mating can be complicated for cardinals. According to another Cornell Lab website, Birds of North America (tinyurl.com/ wi-card-dna), cardinal couples are monogamous socially, sticking together year-round. But the female hedges her bets when it comes to her gene pool: 5-35 percent of cardinal offspring have DNA from males other than her mate. Predation rates are high on nestlings and eggs, with only 15-37 percent of nests producing fledglings.
The day after I saw the cardinal pair, I used my binoculars to look for the nest in the hydrangea. Through the thick foliage, I spotted it about a foot or so in on the side facing into the garden and about 5 feet off the ground. I hadn’t seen much of the cardinals near the bush in the days that followed but had heard them in the yard. Thinking they may have abandoned the nesting site, on July
8 I finally made my way through the tall grass and forbs on the backside of the hydrangea to see the status of the nest.
After determining the female was not on the nest, I carefully pulled aside a few branches to check for
eggs and found three, the same number as in the other cardinal nest I’d found. Although I’d brought my cameras, the foliage was too dense to take photos without breaking some branches, so left without taking any.
I’ll continue to monitor the behavior of the adults to determine if they’re minding the nest but will avoid getting near it again for the next week or so. Repeatedly going to nests not only can disturb birds, which may abandon the nest, but can also create a trail that leads predators to the nest.