The Avian Trans-Gulf Migrants Are Here!

We continue to have some very beautiful sunrises and this was the view April 6 from my bedroom window. It is hard to get up on the “wrong side of bed” when this panorama is in front of you!

One beautiful spring flower is the prickly pear cactus which has a very large yellow bloom. This one is being visited by a native green bee.

One of the most exciting natural events in April and May is the periodic and rather unpredictable arrival of avian trans-Gulf migrants in Florida. Birds are in the process of flying from the Yucatan peninsula directly north across the Gulf of Mexico heading for N America during their breeding cycle. As west to east storms sweep across the Gulf they pick up migrating birds and push them to the east until they arrive in Florida. As you can imagine being swept along by a powerful storm is an exhausting process and the birds arrive very tired,, hungry and thirsty. They literally “fall out” of the sky and appear in sometimes inappropriate places including yards. After a westerly storm, orchard orioles appeared in our yard on April 4 and stayed three days before continuing their migration north. They were accompanied by eastern kingbirds, and a female hooded warbler. An adult male Cape May warbler was seen at nearby Wildflower Preserve in a blooming bottlebrush tree. Many migrants are dependent on finding water and food quickly which we supply with dripping water baths and a variety of flowers (especially Cape and coral honeysuckles and fruit, primarily mulberries, red, black and white). Orchard orioles are unusual in that they are flower piercers with a very sharp pointed bill which they use to obtain nectar from the base of flowers (the backdoor entrance). Our goal is to provide a waystation for these trans-continental travelers to provide a place for recovery and refueling for their strenuous flights to the north. Warblers feed on flowers such as bottlebrush and sea grape flowers (which are still in bud) and forage on the ground and in trees.

We also still have some of our winter resident warblers such as palm warblers (now in their striking breeding plumage) which will be migrating far to the north. Prairie warblers are likely winter residents that will be breeding locally in the mangroves, or flying to northern Florida and beyond to eastern N America. Our resident screech owl pair are breeding in our owl box; the reddish morph female sticks her head out of the box periodically to see what is going on in the world outside.

Native carpenter bees are quite active in collecting pollen and nectar such as from this non-native primrose willow. Carpenter bees have an interesting means of accessing nectar from the native coral honeysuckle which has a very long narrow corolla tube too small for its mouthparts- it simply bites into the flower and “steals” the nectar without fertilizing the flower.

At Wildflower Preserve I came across an interesting fly visiting flowers. This apparently unremarkable insect has a bizarre life history- it is a “bee fly” that is a parasite on caterpillars but also a “hyperparasite” of other fly parasites: https://beetlesinthebush.com/2016/12/14/the-black-bringer-of-light/

The recent warmer weather has brought out a variety of dragonflies which caused me to scramble a bit to remember the names of odonates not seen for many months. Dragonflies represent a very primitive evolutionary line yet are behaviorally quite sophisticated. These four species of medium-sized species illustrate some of the beauty of form and color. Three are females, the amberwing, four spotted pennant, and marl pennant. The male seaside dragonlet is a species that quite uniquely is able to tolerate highly saline water as an aquatic larval form. It is unusual for insects to survive in very salty water. When I was in the FL Keys during a sabbatical studying crocodiles in FL Bay I took the opportunity to study this phenomenon in some detail and published a 1980 paper on the subject ( Adaptations of nymphs of a marine dragonfly Erythrodiplax berenice to wide variations in salinity. Physiological Zoology 53(4): 445-452).

A major pleasure of spring is observing the intense green flush of new growth in vegetation, especially in marshes. This is a view of the western side of Moorhen Pond at Wildflower Preserve illustrating the current status of the plants. Much effort has gone into managing the pond to encourage growth of native vegetation which is not aggressive in crowding out other species. But successional changes are quite difficult to resist and if you come back in 5-10 years things might look quite different. In any case it is a beautiful vista to enjoy.

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