Otter Point Creek Newsletter
by Kathy Baker-Brosh, Ph.D.
Honey bee hives are stinging from the effects of a new problem. Colony Collapse Disorder (CCD) has entered the ecological picture, plaguing hives across North America and other parts of the world causing bee colonies to die out. Before CCD became noticeable, beekeepers generally lost 30% of their hives to disease-causing organisms. Recently in some areas, 60-100% of bee colonies are being lost due to CCD. Beekeepers in Maryland are reporting the disorder, although at low levels. It’s expected that the problem will re-emerge this summer, with more widespread effects.
The precise cause or causes of CCD have not been determined as yet, but scientists recognize that a combination of factors has contributed to bee decline in recent years. Because honey bees are not native to North America, they are already vulnerable to many disease-causing organisms found here. Although these other pathogens can cause bee colonies to appear “sick” with lackluster bees, deformed larvae, or dead bees inside or outside the door to the hive, the symptoms of CCD are distinctive. With CCD, there is an absence of adult bees in the colonies. The forager bees appear to leave the hives and not return. Few or no dead bees are found around or inside the hive and there is often the presence of developing brood (bee larvae) with few adults tending them. Because bees have a social hierarchy, their number one goal is to take care of the brood, but with CCD the brood appears to be abandoned. Often there are plentiful food stores which would normally be highly desired by “robber” insect species, but oddly, the honey and wax are not immediately raided: robber bee and moth species avoid the hive. Honey bees found in the hive during colony collapse appear to be stressed and have a suppressed immune system with disease-causing viruses and fungi present in their guts.
Laboratories across the country have been working to find the cause of CCD. Research by scientists here in Harford County at the Edgewood Chemical Biological Center indicates the cause of CCD may be a virus or a micro-parasite. Their work, in conjunction with scientists at UC San Francisco, confirmed the presence of new viral pathogens in honey bee samples. The scientists at ECBC used a cutting-edge technique, designed for military use, which can rapidly screen samples for disease-causing organisms. Other researchers at Columbia University’s Mailman School of Public Health also found a virus in honey bee populations that may contribute to CCD. The virus is called Israeli Acute Paralysis Virus (IAPV). The symptoms of the virus include shivering wings, paralysis, then death, often just outside the hive. Although these symptoms are not the same as those found in hives decimated by CCD, the presence of IAPV in hives is very strongly linked to Colony Collapse Disorder.
Some scientists are investigating the effects of exposure of bees to a group of pesticides including imidacloprid, used commercially and also commonly bought in home and garden centers as the product “Merit”. Imidacloprid is a systemic pesticide (incorporated into the plant tissues) that scientists fear may also be present in nectar and pollen. This pesticide works to control pests in two ways. First, insects become disoriented after ingesting it. This makes it particularly good for controlling pests such as termites which, after foraging, cannot find their way back to the colony to deliver food to the larvae. Second, it has an immune-system suppressing quality to it, causing the insects to become vulnerable to pathogens they might otherwise fight off. These same symptoms: failure to return to the colony and immune suppression, are seen in CCD. “Merit” has become a common and standard treatment for turf pests such as grubs, and is recommended by Bayer (which manufactures it) as a safe choice for integrated pest management (IPM). Investigations into the possibility that these pesticides are contributing to or causing CCD are ongoing but complicated.
It is likely that a combination of factors have led to Colony Collapse Disorder. Certainly the strong link between Israeli Acute Paralysis Virus and CCD is intriguing and scientists are now identifying ways to stop the spread of this pathogen. Honey bees are already stressed from habitat loss, a convoy of other pathogens, and exposure to pesticides and could be reaching the tipping point as this new virus enters the scene. Whatever the cause or causes may be, Colony Collapse Disorder is a worrisome development. Honey bees pollinate about one third of our food supply around the world and so are worth far more than the honey people consume.
by Jessica Baylor, Weekend Naturalist
We all know the massive yet graceful adult bald eagle by its bright white head and tail soaring above our heads high in the sky. The bald eagle’s scientific name, Haliaeetus leucocephalus, means a sea (halo) eagle (aeetos) with a white (leukos) head. (At one time, the word “bald” meant white, not hairless.) If you have ever flown in a commercial airliner before, chances are you were flying at heights somewhere around 30,000 feet above the ground. Bald Eagles (Haliaeetus leucocephalus) can soar at heights up to 10,000 feet, reaching flight speeds of 30-35 miles per hour. The average wingspan of a bald eagle is an enormous 72-90 inches. The bald eagle has hollow bones, over 7,000 feathers, and weighs in at 10-14 pounds.
It is the eagle’s keen eyesight that enables it to hunt so efficiently, and that gives rise to the age-old phrase “eagle-eyed”. Their vision is 3-4 times stronger than a human’s. Bald eagles are generally fishermen, swooping down and using their sharp and massive talons to catch fish that include catfish, perch, bluegills, herring, and carp. Other prey include small mammals or reptiles such as muskrats, snakes, frogs, and even turtles. Once the eagle has returned to a safe location to perch, it will begin to use its razor sharp beak to tear apart the catch of the day. Bald eagles need to be wary of any nearby raptors such as ospreys that will challenge the eagle’s fresh catch and try to steal it. In the winter months, when the waters of the Chesapeake Bay are frozen, bald eagles can be seen scavenging on carrion such as white tail deer. As many as 20 eagles may try to feed upon one deer carcass.
Bald eagles prefer habitat within a mile of water or open wetlands and are known as short distance migrators. The Chesapeake Bay bald eagles can migrate north to Maine and south to Florida, depending on the seasons. There are also year-round resident eagles in the Bay region.
Bald eagles mate for life. If one of the pair dies, then often the remaining mate will pair up with another eagle, but this may not always be the case. Bald eagle chicks in the northern Chesapeake Bay region can hatch as early as March and as late as May. The number of chicks in a bald eagle nest ranges from 1-3. Remember that razor sharp beak used for tearing apart food? It is also used in a very controlled and gentle manner to feed the young.
Both parents keep a vigilant watch over the young for 3-4 months, in and around the nest. Even after the young chicks fledge the nest the parents will still feed the young birds, as hunting can prove to be quite a challenge for the young of the year. (Fledging the nest is a fancy term meaning to fly from the nest for the first time.). The first flight from the nest often begins with the young eagle hopping to a nearby limb, then another, then another, and finally it will spread its wings and take the plunge. The first flights are always short as the young eagle tires quickly, but with age and practice comes strength and endurance.
Young eagles grow into sub-adult bald eagles, and begin to roost at communal roosts each night. Groups of eagles gather in large numbers at communal roosts for safety, protection, and possibly for social reasons. Some scientists believe the roosts are a gathering place where sub-adult or even young adult birds can begin to pair up with one another.
The bald eagle has made a magnificent recovery from the previous status of threatened and endangered. They have been “de-listed”, but still need our respect and vigilance to assure healthy populations in the future. Everyone should have the chance to see this huge bird soaring in the sky, flashing its white head and tail.
by Candace Morrell, Stewardship Coordinator
Invasive species like the Northern Snakehead Fish, the Zebra Mussel and the Nuclear Worm have been in the headlines for a few years now. Some of the species that threaten the Chesapeake Bay National Estuarine Research Reserve sites in Maryland, like the Nutria, Purple Loosestrife, Phragmites, Hydrilla, Japanese Honeysuckle, Garlic Mustard, and Multi-flora Rose, are more subtle in their invasive strategies, and are sneaking in and taking over.
The problem with invasive species is they damage natural systems by upsetting the ecological balance. They disrupt the intricate web of life for native plants, animals and microorganisms, many of which are already rare. Invasive plants crowd out native plants or crops; are often of less value to wildlife than native plants; eliminate native host plants needed by insects; and cause a general decline in the diversity of life on which we depend.
These species were introduced, either intentionally or accidentally, by people, and can potentially multiply rampantly, eat, displace and/or infect native plants and animals. This is a real concern to natural resources managers.
Local climate, geology, soil, available water and other natural factors influence which plants and animals can live in a particular ecosystem. Species that have evolved in a particular place are native to that place. Non-native plants and animals are those that have been introduced from other continents or states, as well as other habitats.
Not all non-native plants and animals are invasive. Invasive species are aggressive spreaders and reproducers. They can also adapt to a variety of conditions; move about easily, either on their own or by hitching a ride on wind, water, wildlife, or people and their equipment; have few natural controls, such as predators or diseases to keep them in check; and are difficult to control or eliminate once they become established in the wild.
We are forming a club of brave soldiers to help get rid of non-native invasive plants on the Reserve. The team name is “The Invasinators”. We have been meeting monthly to remove invasives from Leight Park. In mid-July at the Anita C. Leight Estuary Center, we will focus on purple loosestrife. We will dine on “Everything Purple” and learn about our enemy and how to defeat it. We will then go out to the trenches to eliminate it! We will have a second session of battle a few weeks later. For those who want to join us for at least two sessions, you will be rewarded with a very cool T-shirt. Check the Estuary Center Calendar of Events for exact dates. See you there!