Techniques and Purposes of Avian Monitoring
Monitoring is usually done by surveillance of species via aircraft as
the selected groups remain in large, easily identifiable groups.
Because of their immense populations, sometimes thousands of birds,
direct counts are not necessary to determine population decline.
Instead, simply calculations can be implemented regarding area of
congregations and approximate concentration (birds/meter2).
Marine avian species are also easily extracted for further
study of their diet and for concentrations of hazardous chemicals,
such as heavy metals and pesticides. As these creatures are at the
top of their respective food chain, their health can be indicative of
the entire system. Also, concentrations of hazardous materials
within organisms generally increase as one climbs the animal
hierarchy. As sea birds obtain their diets entirely from the marine
environment, they act as the most easily study bioindicators for
human/industrial wastes. Bird viruses, which spread rapidly, as well
as breeding successes (usually determined by clutch size and juvenile
health) can also be studied via sampling.
The coupling of marine avian population studies and other
marine sensoring system creates a balanced equation that improves
ecological understanding of cause and effect. By studying these
populations in sync with abiotic marine factors, issues of concern
will be directly identifiable.
Analyzing Individual Birds
Part of the avian monitoring plan icludes studying individual birds by
removing them from healthy populations, then taking them back to the lab
for more detailed analysis. Laboratory analysis gives data much more
specific to the health of an individual bird than images of the whole
population. This analysis will determine, among other things, diet,
diseases the bird may carry, and the bird's general state of health
and fitness.
This data becomes extremely important in the case of diseases and
diet. Avian diseases are quick-spreading and often deadly, and it may
be necessary to work to stem the epidemic by eliminating carriers of
the disease or other means. As far as diet is concerned, consider a
single bird that has a toxin in its tissues. If this toxin is
environment-related (i.e. a heavy metal), it can be concluded with
some further research that the entire population living in some area
may be at risk, and solutions to remove the toxin must be implemented.
There are several traits desired in a practical candidate for study:
1. It should be a relatively nonmigratory and stable species; birds
with known routines are the most desirable.
2. The best candidates are purely carnivorous and obtain the
predominant amount of their food from the marine environment.
3. It should be a relatively large or social bird. This simplifies
monitoring and study. Birds don't have to be exactly counted, they
can be monitored via ultralight aircraft.
4. Most accurate studies usually use crane-type birds, as they are
particularly large and are less adaptive to human interference.
Gulls, for instance, adapt easily to urban or developed areas; this
particularly hearty quality makes them less appropriate for analysis
of wild systems.
Possible Candidates for study include:
1. Herons: Great Blue, Yellow Crowned Night, Galapagos, and Striated.
Herons are excellent candidates because they feed almost entirely in
estuarine or near shore environments, are quite large, have easily
identifiable nesting sites and are usually non-migratory.
2. Brown Pelican: an endemic subspecies of the common south american
variety that feeds in a range usually no greater than 20 miles from
shore. They fish in primarily shallow waters and tend to flock
together. They are another large species with communal nesting sites
that could be easily monitored.
3. Blue Footed Booby: A very common South American sea bird that
breeds throughout the Galapagos. It's primary diet consists of small
fish, specifically anchovies, and they have very large nesting sites,
consisting of thousands of birds. They're dependence on anchovies
makes them a particularly good candidate as does their social nature.
They could be easily monitored via approximate population counts with
more specific testing done by extraction of single samples.
Monitoring Birds with Unmanned Controlled Aerial Vehicles
In order to monitor birds, it was determined that the most efficient way to do so was to monitor the birds' nesting sites and movement in their environment. This is the best way to monitor birds because it gives information about reproductive behavior and it is a place to which birds regularly return, so it is easy to keep track of the birds being monitored. It was also thought that monitoring the nesting sites would be easier and safer for the birds than tagging the birds directly. Some of the non-avian terrestrial endangered species will be tagged, but in the case of birds it was thought that since the birds continuously return to their nesting sites it would simply be a more efficient way of monitoring the bird species. Also, birds are very fragile creatures with hollow bones, and attempting to capture and tag a fragile bird may cause more harm than attempting to capture and tag an iguana, for example.
The plan is to build a remotely operated helicopter with a digital video camera attached that will fly over the birds' nesting sites. This camera will take pictures of the nesting sites in order to determine how many birds are at the site, whether there are empty and/or damaged nests, and how well the birds are breeding.
There were several options discussed as to what the vehicle carrying the camera should be. These options included a manned aircraft, an unmanned radio-controlled airplane, a radio-controlled helicopter, and an unmanned airplane or helicopter controlled by a computer program. A manned aircraft was ruled out because it would be very invasive and the fuel emissions would be much higher than the other options, destroying the environment we are attempting to save. Also, if something unfortunate occurred such as a bird flying into the craft causing it to crash, a human life would be lost as well as the craft. There are also only two airports in the Galapagos, so flying to some of the outlying islands would be difficult and add further to the fuel emissions. An unmanned radio-controlled airplane or helicopter flown by a computer program was also ruled out. It was thought that the programming would be very difficult but feasible. However, if the aircraft needed to adjust its course for any reason, such as a bird flying directly in its path, the aircraft would not be able to adjust its course because the program would be set. A radio-controlled aircraft was the option left. However, the question of the benefits of an airplane versus a helicopter was brought up. The helicopter was finally chosen over the airplane. It was thought that in case the scientist controlling the plane saw something that he wished to examine more closely at that moment, it would be easier to stop a helicopter and have it descend and hover over the site of interest than to bring the plane back around, and only be able to get fly-by pictures. Having a helicopter also means that no runway is needed.
The remote-controlled helicopter will be controlled by a scientist aboard a catamaran sail boat. This boat will act as the command station and also as the platform from which the helicopter can take off. The boat will travel around the coasts of the islands because most of the nesting sites to be monitored are located near coastlines. Further, during the course of its travels it will be used to evaluate the level of corrosion and the state of the ocean buoy sensors to determine whether further maintenance or replacement of certain parts is required.
The remote-controlled helicopter design that will be the base for the design was designed by the Hovercam Company that describes their design in the following manner: "The HoverCam® is a conventional two bladed rotary wing helicopter. It will be powered by two 13.1 cm3 single cylinder two-stroke engines. It has a +6g capability and is used for the carrying of commercial film cameras and down links. It is mainly of carbon epoxy construction, the camera mounts which are made of carbon-reinforced epoxy resin and foam sandwich. The rotor blades are constructed from carbon-epoxy foam laminate. The tail rotor blades are constructed from carbon-epoxy foam laminate. The main rotor head is constructed from steel and light alloys. The tail rotor gear box is constructed from light alloy and has steel helical drive gears. All shafts are balanced and single direction thrust races are used in high load areas e.g. main and tail shafts and blade holders. Tail drive shaft is a hardened aluminium torque tube, with universal joints at each end of the drive chain. The engines are linked to each other by centrifugal clutches and one-way brag bearings which drive the main gear chain, which is linked to the main shaft by a freewheel bearing which acts as the auto-rotation unit."
The Hovercam(R) has a single cylinder, five Schnuerle posted engine with rear induction, rear exhaust, and direct drive. It is air cooled and timed for a tuned exhaust pipe. The displacement is 13.1178 cubic centimeters. This engine runs on fuel that is composed of 10% synthetic oil, 5% castor oil, 70-75% methanol, 5-16% nitro methane, and 5-16% nitro is recommended. The rotor is two-bladed with a diameter of 1.75m and a rotor disc area of 2.41m. The altitude from ground level at which it flies is 100-180m with a speed of 0-95km/h. The maximum range from the operator is 200-250m. The maximum take-off and landing weight is 21kg, so the maximum payload weight is 11kg. Twin battery packs are employed, and the remote control system has a 35 MHz or 72 MHz backup.
Improvements to this design would include a method of noise reduction on the engine so that the birds are not scared away or their living patterns modified by the intrusion of such a devise into their ecosystem. Since only a camera is being carried, the maximum payload value is adequate. Further, it is important that the camera be equipped with a rather high zoom lens that has a changeable depth of field so we can magnify and focus the lens depending upon how near we are to the subjects. The fuel may also be experimented with and eventually modified in order to become more environmentally friendly while still providing robust performance for data collection.
The helicopter will be flown regularly during the mating and nesting season in order for the birds to become used to its presence and to exhibit normal behavior when the helicopter is monitoring the area. The helicopter will be flown and pictures will be taken once every two weeks per island. The plan is to fly the helicopter during the day. However, if it is found that more information about the nocturnal habits of a certain species of bird is needed, the helicopter can be fitted with a night-vision or thermal-imaging camera and flown at night. The current camera that will be placed on the helicopter is a digital video camera with a high number of pixels for the best resolution possible. The helicopter should invade as little as possible, so being able to take high-quality photographs at a far distance is important. This sensor will become even better as digital camera technology develops.
Sources
Hovercam Industries.(2004, May 2) Helicam Technical Specifications [WWW Document]. URL http://www.hovercam.com/equipment/helictech.htm (visited 2004, October 11).
