Thorny subject, protecting birds

Birds are a joy to listen to and to watch.  What backyard is complete without them?  Sadly, songbird populations have declined steeply over the past four decades.  Habitat destruction both here in North America, where many species nest and rear their young, and in the warm Caribbean islands and areas of Central America where neotropical bird species migrate to spend the winter months is a major factor in this decline.  Other factors include a lack of food resources and over-predation by introduced animals, ie: animals not native to an ecosystem. (Ehrlich, Paul R., Dobkin, David S., and Wheye, Darryl. The Decline of Eastern Songbirds. 1988)

How do we protect our birds?Southern Dewberry, Rubus trivialis

Nesting space: Plant shrubs and vines with protective vegetation.  Thorny shrubs, plants and vine tangles will help to protect nests and nestlings.  Slender, thorny stems will help prevent larger predators such as raccoons and cats from attacking nests and stealing eggs or killing chicks.  Many thorny shrubs also perform double duties by providing fruit and berries from summer through fall.

  • Low, brambly shrubs such as garden variety blackberries (Rubus spp), or Southern Dewberry (Rubus trivialis), provide delicious nibbles for us humans, while attracting birds and furnishing them with a food and cover.  They can be kept in check in a small yard, but the neater they are, the less cover they provide. Devil's Walkingstick in bloom
  • Devil’s Walking Stick (Aralia spinosa) is an important food source for migratory birds.  In summer it sprouts an enormous (3 foot diameter), misty plume covered with simple flowers that attract all manner of butterflies and other pollinators while blooming.  It will also support 3 to 5 birds feeding at one time when the purple berries ripen in fall, which is quite a sight! Devil’s Walking Stick has one of the largest, lacy bi-pinnate leaves of any plant in North America.  This prickly small tree will form a fairly large colony and would do well in a back corner of a large yard.
  • Hawthorns (Crataegus spp.):  these are an underused, extremely handsome group of shrubs/small trees.  When mature, their small rose-like flowers range in size from 1.25 inches across to clusters of smaller, 3/8 inch flowers.  Their slender branCrataegus species.ches usually have thorns making it doubly hard for larger predators to climb up to nesting sites. The fall sees hawthorns covered in small fruits that can be enjoyed by birds and humans alike.

Cover: A Safe Haven

After fledging, but before becoming flight savvy, nestlings need cover: places to flee from neighborhood cats and dogs.  Here are a few ways to thwart Tabby and Fido from making a snack out of local baby birds:

Fern patch:  Provide a densely planted fern thicket in a shady side border.  Low, moist areas in the back yard are perfect for hardier ferns such as Southern Shield (actually a coastal plain species, fine for gardens but not restoration) or Southern Lady Fern, or Christmas Fern.  Cinnamon Ferns, Royal Ferns, Beech Ferns, and Sensitive Ferns are also good cover, but need a consistently moist location.  Bracken Fern makes a wonderful escape for chipmunks and nestlings.  The stems are tough, the fronds can be three to four feet tall, and the plant will survive 6 hours of sun a day and fairly dry soils.  

I have seen cats completely flummoxed when trying to pursue an animal into a thicket of bracken fern.  However this fern is too aggressive for a small yard, it needs a big, broad area to spread out in benign neglect for both you and the fern to be happy.  If you have an untended railway siding nearby, or own some wild acreage, this might be the plant for you.

Brush pile:  A loosely bunched brush pile in the back of the yard is a very effective way to deter predation of small wildlife.  Brush piles don’t have to be huge, but should be large enough to keep a persistent cat from getting to the center.   The moist, slowly decaying wood at the bottom of the brush pile also creates an excellent habitat for tiny wildlife such as salamanders and larger limbs can provide homes for mason bees.

Do not use pressure treated wood products in your brush pile.  Pressure treated wood is toxic, and will poison the small wildlife and beneficial insects that both feed the birds and benefit your garden.

An added long term benefit of keeping a small brush pile at the back border of the yard is that it will gradually enhance your soil biology, providing food and homes to beneficial soil fungi and bacteria.   After a few years the soil under the brush pile will have become very rich, at which point you might want to start a fresh brush pile in a different corner of the yard as you consider which humus-loving native plant(s) to place in your newly enriched bed.

Sources:

Ehrlich, Paul R., Dobkin. David S., and Wheye, Darryl. The Decline of Eastern Songbirds.  http://www.stanford.edu/group/stanfordbirds/text/essays/Eastern_Songbirds.html. Stanford University. Stanford.  1988