Birds and Butterflies
Birds & Butterflies
Plants aren't the only thing living in our gardens - they are also the home of birds, butterflies, and a host of other animals and insects. Learn about our friends and foes that share our yards and neighborhoods.
By Julie Jansen
The premier time to find scarlet tanagers is during the first few days after the males arrive in spring. The males arrive earlier than the females and start singing from the tops of big deciduous trees that are just coming into bloom. The males can see each other easily amid the foliage, and neighbor faces off against neighbor. Each stakes his claim and defends his desired territory against other males. At length, one male drives away all intruders and secures his territory. When a female gets there a few days later, abruptly the sovereign male goes quiet. He does not resume loud, conspicuous singing until nest construction has begun, but only rarely throughout the nesting season does he again sing from treetop perches.
The Dating Game
During the courtship period, a male sings seldom and only short, soft songs. If you are lucky enough to locate a courting pair, you may see the male drop quietly to a perch near the forest floor in a location where the female has an unobstructed view of him. Normally his black wings cover much of his scarlet back, but now he positions his wings outward from his body. The female can’t help seeing the dazzling red of his back, bordered by perfectly black wings and tail. He flies from one low perch to another, tracing a large semicircle on the forest floor. At each new landing spot, he pauses, posing like a model for a photo shoot. Overhead, the female traces a similar route, staying above him and watching him closely as he displays.
A female starts building a nest within a week after arrival, without help from the male. She can have the nest done in as little as a day or two, or it may take her up to a week. While she works, the male starts singing loudly again. Occasionally the female sings also. Only the female incubates the eggs. Both parents feed the young, though the male’s contribution varies from bird to bird. Nestlings receive caterpillars, adult insects, and fruit. Other frequent menu items include the abdomens of insects, from which the parent has tenderly removed the legs, wings, and heads.
The scarlet tanager leads a double life. Every fall, after the breeding season, the entire population picks up and moves to South America. The technical term is “complete migration,” meaning that there is no overlap between the summer and winter ranges. Reports in winter reveal them in Colombia, Ecuador, Peru, and Bolivia. Information about their lives in South America is scant, but scarlet tanagers do not breed there. It’s thought they spend this second summer singly or in small mixed flocks among mountain forest slopes. There is no evidence of pair bonds in winter. In South America, male scarlet tanagers are not scarlet. Because they do not breed in winter, they don’t have to defend territory or engage in courtship. Thus, they have no need for attention-getting plumage. Before they go south, males molt. Their bodies turn green, like females, but their wings remain black. In late summer, you may see a male half molted, with splotchy patches of red and green body feathers. Before their northward spring migration, males molt back to red again. Then they have fresh, unfrayed feathers for the arduous flight.
We don’t know the details of their route. We do know that most fly across the Gulf of Mexico, a nonstop journey of some 600 miles. Moreover, scarlet tanagers don’t start their migration from Central America, the way most neotropical passerine migrants do. They’re coming all the way from South America, probably through Venezuela or Colombia.
BirdWatcher’s Digest May/June 2020 issue
Eastern Black Swallowtail
The Black Swallowtail likes open habitats. It is found in fields, meadows, deserts, marshes, near lakes and streams, farms, lawns, near cities, near roads, and gardens. It is rarely found in forests or woodlands.
Humans have greatly helped the Black Swallowtail. They brought non-native carrot species from Europe to North America. The Black Swallowtail uses these plants as host plants. Before humans cut down forests, Black Swallowtails were rare. They were only found in small prairies, wetlands, and openings in forests.
The Black Swallowtail flies very fast. Its flight is much quicker than other swallowtails. The Black Swallowtail flies closer to the ground than other swallowtails do. In cold weather, they will hold their abdomens above their wings, this keeps them warm. Usually, Black Swallowtails live about 10 to 12 days. Some however, can live up to 35 to 40 days. Some of the food sources for the Black Swallowtail are milkweed, butterfly weed, thistle, purple coneflower, alfalfa, lilac, ironweed and zinnia. Males will also come to damp soil and mud to feed on minerals and moisture. This is called puddling.
The Black Swallowtail goes through complete metamorphosis. The territory is usually on the top of a hill. The male will sit on high branches or other vegetation on the hill. He will defend his territory from other male Black Swallowtails. If other males come too close, he will chase them away. The female will fly to the top of the hill to look for a mate. A successful courtship lasts for about 40 seconds. Females that do not want to mate will try to escape from males by flying high in the air and then quickly flying downward.
Female Black Swallowtails fly close to the ground to look for host plants. Females lay one egg per host plant. The eggs are laid on the leaves and flowers. The egg is yellow. It later forms a red ring around the center, and then a red top. It will turn dark gray just before hatching. It takes about 10 days to hatch. In a lab test, females laid a total of about 200 to 430 eggs. They laid about 35 to 50 each day.
The caterpillar will eat the leaves and flowers of the host plant. The young caterpillar is black and has a white spot in the middle of its body. This spot is called a saddle. It mimics a bird dropping. The older caterpillar is green and has black bands with orange spots in each of the bands. The caterpillar has a special organ called an osmeterium. It is an orange, bad-smelling organ. It is shaped like a snake's tongue. It is kept behind the inside of the hea The caterpillar releases it to scare predators away. The caterpillar will reach a length of 2 in.
The chrysalis hangs upright. There is a silk thread around the upper part of the chrysalis. This thread is called a girdle. The chrysalis is either brown or green. The Black Swallowtail will hibernate as a chrysalis.
Adult butterfly The Black Swallowtail has a wingspan of 2.7 to 4 in. The upper side of the male's wings is black. There are two rows of yellow spots along the edges of both wings. There is a small area of blue on the bottom wing between the two rows of yellow spots. On the bottom edge of the bottom wing, there is a red spot with a small black dot in the center. The upper side of the female's wings is black. There are two rows of light yellow spots along the edges of both wings. These spots are smaller than the male's. There is a large area of blue on the bottom wing between these two rows. The female also has the same red and black spot on the bottom wing as the male. The underside of
the wings is the same in both sexes with the top wing being black with two rows of yellow-orange spots. The bottom wing has two rows of orange spots with a blue area between them.
Report by Julie Jansen, sources: wiki.kidzsearch