Posted by: lensweb | September 30, 2020

Feed the Birds (but you may get more than you bargain for)!

Bird feeding is a wonderful way to attract birds to a garden or wildlife site. A lot of people feed birds in the winter, supplemental food from feeders is an easy and convenient resource for birds in the competition for food. More natural food sources are available during the summer months, such as flowers, insects, fruits and natural seeds, but these natural foods may no longer be available in the immediate area and birds are overworked trying to provide for hungry broods of growing nestlings, so sometimes it is best to continue feeding throughout the year. By feeding birds in the summer, it is possible to attract different species in your garden such as jay, nuthatch or woodpecker, and a reliable food source will train young birds to return the following year.

But, when birdseed is broadcast, you may attract more than birds into your garden or wildlife site! Most birdseed manufacturers sell baked birdseed which has been subject to heat treatment eg at 120º C for 15 minutes. Thoroughly baked seed will not germinate, but will still attract birds, but viable seeds may escape inefficient process.

Autumn is the time of the year when some exotic plants and flowers may be found flowering under the bird feeder in the garden. In a1985, study, Hanson and Mason (Watsonia 15) found that 30 species of plants regularly appear as bird seed aliens. Cultivation of bird seed samples from many sources produced a 1ist of 438 species of plants.

Here are a few which I have found: Wheat Triticum aestivum, and Barley Hordeum vulgare, as common agricultural species are hardly noticed. Wild Oat Avena fatua is a well known noxious weed. Sunflower Helianthus annuus seeds are one of the most popular seeds for bird feed mixes and now often turn up ‘in the wild’.

Introduced alien plants may cause problems for agriculture: Niger seed or Blackseed, Guizotia abyssinica a favourite of the goldfinch, is native to Ethiopia; Black-eyed Susan Rudbeckia hirta is native to America, common millet or proso, Panicum miliaceum is an annual grass which has a short growing season, and needs little water. Cockspur or “barnyard grass’ Echinochloa crus-galli is a type of wild grass originating from tropical Asia considered one of the world’s worst weeds. Canary grass Phalaris canariensis,is a grass native to the Mediterranean region, it is now grown commercially in several parts of the world for birdseed. Datura stramonium, known as thornapple, or jimsonweed, is a poisonous plant in the nightshade family which originated in Mexico, but has now become naturalized in many other regions. The shoo-fly plant Nicandra physalodes is an attractive flower which pops up unexpectedly, around bird feeders. Common Amaranthus or Pigweed, Amaranthus retroflexus is now common, spread by bird seed.

Hemp Cannabis sativa, indigenous to eastern Asia, is now found worldwide due to widespread cultivation, it has 1200 common names! The flower is a wind pollinated annual, with palmate leaves, the branched male and unbranched female flowers are on separate plants. It is not clear whether penalties apply for the inadvertent cultivation of this plant.

Birdseed won’t grow if it doesn’t reach the ground. Putting a tray underneath to catch overflowing seeds can prevent the potential problem of weed or alien plant growth. Although birds may be messy eaters, squirrels are sometimes a bigger problem. If squirrels are scattering seeds, consider another type of feeder. When birdseed is broadcast you may attract more than birds into your garden and this may have greater consequences for the natural environment.

Marion Bryce

23 September 2020


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