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Tag Archive | "Nesting records"

Nesting records


By Ranger Steve Mueller

 

Many species are nesting though it might seem early because it looks wintery brown. Rabbits, mice, shrews, and other mammals are producing families despite the cold, dreary brown pre-spring appearance of neighborhoods. Bald Eagles, hawks, and owls have eggs or young in nests. The timing for predatory birds to have young in the nest is linked with the other species young leaving nests. February eggs in the nest is normal.

It is important adults find enough food to supply rapidly growing young with nutrition. A young owl or hawk that hatches first gets a head start on growth. If the first hatched is satisfied with a full stomach, other birds in the nest might get to eat. When this is not the case, others go hungry or might be pushed out of the nest by the larger sibling. When predators are searching for prey it is good when many of the prey’s young are just out of the nest. They are easier to capture and can be abundant. 

Population replenishment is better when one owl or hawk survives than for two or three to die of starvation. When prey populations are doing well the predator population can do well and produce more than one young. 

I have observed a Great Horned Owl fledge three young. Bravo! Normally, I encounter nests haphazardly by chance. Birds have a good knack for hiding nests. One March I flushed a Horned Lark and noticed it left a nest. I sat nearby waiting for its return. When it came back, it landed a distance away and sneaked through the vegetation on foot to the nest where it continued incubating. I noted behavior and other interesting details.

The next day, three inches of snow covered the landscape. The adult bird kept the eggs in its well-hidden nest warm. I returned to observe the nest until the two young ventured into the world on their own. I numbered that nest 1971-2 in my journal. It was the second nest I found that year. When I encounter a nest and note it in my field journal, it receives a number that follows the year. If I observe the nest repeatedly to monitor development and nesting success, the nest number remains the same, but the new date and activity are documented. For 1971, I had 65 separate nest discoveries. 

Interesting observations are recorded that hopefully will add to our understanding of bird ecology. Last year I found a Yellow Warbler nest with six eggs. At Fernwood Botanical Garden and Nature Center, I found a Wood Thrush nest with five eggs but one was not a thrush egg. It was a Brown-headed Cowbird egg. 

Cowbirds have a nature niche adaptation to follow bison that were constantly on the move grazing prairies. By laying eggs in other birds’ nests, cowbirds can continue to follow bison eating insects stirred by the bovines. Cowbirds were not a natural part of Michigan’s European pre-settlement wildlife communities. When we reduced the forest cover, cowbirds expanded their range. The adventive establishment of cowbirds to new habitat created survival risks for many bird species. 

Young cowbirds are raised by the parasitized species adult. Often the baby cowbird pushes the parent’s eggs or young out of the nest and will be the only bird to fledge. I removed the cowbird egg from the thrush nest and set it on the ground for a chipmunk or other small mammal to discover and eat. Hopefully a cowbird adult did not return to lay another egg in the thrush nest. 

It is good to avoid nests for a number of reasons. A mallard cracked an egg when it rapidly flushed from a nest when people approached. Eggs left unattended might be preyed upon or lose heat needed for development. Walking to nests can create a scent path that predators like raccoons or opossums use to find nests with eggs or young. Rarely do I monitor nests. I note what I discover and hope the bird successfully raises a family.

I note the species, habitat, nest location, tree species used, height of nest among other details such as behavior. Nests records are entered to ebird and will be available for others to review the what, when and where for bird nesting well after I am dead. You can become a part of citizen science data gathering and add it to ebird. 

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.

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