Howler monkeys face dangers in Laguna de Apoyo Nature Reserve

Even in fairy tales, not all endings are happy. This week, we were witnesses to a tragic story with a silver lining. Along the northern shore of Lake Apoyo, howler monkeys have proliferated, so much so, that Laguna de Apoyo Nature Reserve is now among the best locations in Nicaragua for monkey watching. Golden-mantled howler monkeys regularly enter the areas where housing was constructed in the 1960's and 1970's, between the access road and the lake. (White-faced capuchin monkeys also inhabit our area, but are fewer and occupy very limited ranges.) This means they are entering yards of homes and coming into contact with electric transmission wires. As a group of monkeys moved through the forest and into a neighboring yard, one female monkey managed to cross wires and was electrocuted. When we learned of the event, we were mobilized to do what we could. When we arrived on the scene, the lifeless body of the monkey was still attached to the electric wires, which had shorted out and no longer carrying current. Clinging to her waist was a terrified baby, still very alive.

This baby golden-mantled howler monkey clings to her lifeless mother. Photo by Susana de Winne.

We asked ourselves whether the infant monkey had survived. Mother and baby were about five meters above the ground, the mothers tail and paw locked around the wire and the baby clinging to her mother's lifeless body. After several minutes, the baby monkey raised her head and blinked. We didn't know what to do next, but we were happy to know that one life may not be lost.

Tense moments when a baby monkey's life was at risk. Photo by Susana de Winne.

We were concerned the baby would fall with or without her mother, and suffer a bad injury or death. Additionally, the monkeys had now attracted the attention of several neighbors, and we were also concerned that the wrong neighbors would capture and keep the monkey as a pet. The baby howler monkey was disoriented and anything was possible. We quickly installed a sheet beneath the wires to catch the animals in case the grip of the dead mother would release. And we watched and waited.

The baby monkey continues to cling to her mother. Photo by Susana de Winne.

After another half-hour, the infant monkey 

After another half-hour, the infant monkey climbed off her mother and into the nearby trees. We contemplated whether we should capture the baby, while the baby continued to move. Soon, she was in a tall tree, and we sighed from relief. There are folks who would not hesitate to capture her if they could, to enslave her to the pet trade, a fate nearly as bad as death. We only hoped the infant would quickly reintegrate with her troop, which had departed after the horrible death of the poor mother monkey.

Electrocution by electric utility wires is perhaps the greatest factor in mortality of howler monkeys and other animals in Laguna de Apoyo Nature Reserve. Photo by Susana de Winne.

While we watched the infant monkey, the unscrupulous people who had gathered knocked down the dead mother monkey from the electric cable. We returned to recover her body and prevent others from selling her or using her body for any other purpose. We lingered while watching her body lying on the sheet where she had fallen. Her tail and two limbs were locked in their contracted positions, an adaptation among these animals to allow them to sleep in trees without falling. There were small burns on her hands and tail, otherwise, she looked a perfect specimen in the prime of her life. No fleas or mites were jumping from her body, no injuries or scars were evident. Her half-opened eyes betrayed her final moments when death stole her away. Her breast was full, vainly awaiting her offspring.
We recovered her body, from which we will conserve her skin and skull for scientific and educational purposes. It is our hope to make Laguna de Apoyo Nature Reserve safe and prosperous for the wild animals which need its forests and water. Part of what we do, at times, is no more than give witness to what we see.
Life is hard for humans, and even harder for wildlife. Mortality among monkeys is very high, from our casual observations, sometimes from falling from trees, other times from the cruelty of people, and sometimes, electric wires. Our electrical connections in Laguna de Apoyo Nature Reserve need protectors to save wildlife from the risks of electrocution. Too often, arboreal animals are killed by the wires. FUNDECI/GAIA has discussed the issue of electric transmission wires with MARENA and will be seeking solutions to the risks to wildlife by this modern convenience of man. It is the least we owe our wild neighbors. After all, we live in their yard, not vice versa!

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Jaguar cichlid in Laguna de Apoyo, Nicaragua

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Many cichlid fish species evolved in the Nicaraguan Great Lakes system. Among the more popular of the fish of this region are the guapotes, fish of the genus Parachromis. Guapotes can make a very nice fish dinner. The most abundant of the guapotes in the San Juan River and the Nicaraguan Great Lakes is the Jaguar cichlid, Parachromis managuensis. In Nicaragua, it is known as the guapote barcino, in reference to its checkerboard spotted pattern. Along with several species from the Midas cichlid species complex, the Jaguar cichlid make nests in which parental care observations can be made easily during SCUBA diving.

All the mating cichlids native to Nicaragua protect their young for several weeks after hatching. The guapotes have some important structural advantages to parental care over the more common Midas cichlids found in their range. First of all, the guapotes are large, and therefore can sustain large egg loads. It is not uncommon to see over 2000 fry at Jaguar cichlid nest. Secondly, the guapotes all have large mouths adapted to capture fast-swimming fishes. A bite of the Jaguar cichlid could be fatal even to a medium-sized fish. Potential predators know this and tend to avoid the risk of a bad bite.

These hatchling Jaguar cichlids are less than a week old. They stay near the parental units within reach of a natural or dug cave, and they receive parental care up to about 60 days after hatching. Photo by Martin Cabrera. 

Along with several bird species, the Jaguar cichlid sits atop the food web in Lake Apoyo, Nicaragua. It is the only fish in the lake that can kill and consume up to medium-size fish. Adult Jaguar cichlids only eat fish and perhaps crabs.

Hatchling P. managuensis are prone to move toward the diver, a camera, a hand. Photo by Martin Cabrera.

Male Jaguar cichlids differ morphologically from females in its upturned mouth and other aspects of head shape. Like all the other cichlids native to Nicaragua, the males in breeding pairs always exceed the females in size.

This female Jaguar cichlid is never far from her free-swimming fry. Photo by Martin Cabrera.

All cichlid nests can be fascinating, and the Jaguar cichlids are not unique in this respect. Parents may move little in defense of their fry, but they usually don't have to do much, to get the point across to potential predators.

Most cichlids in Nicaragua utilize natural features such as caves and holes to defend their offspring. This Jaguar cichlid is watching her fry just outside of this crevice. Photo by Martin Cabrera.

Breeding seasonality of the Jaguar cichlid is not as strong as in the Midas cichlids in Lake Apoyo. Whereas the Midas cichlids may reproduce in only two to four months during the year, the Jaguar cichlid is found in reproduction most of the year.

A female Jaguar cichlid (P. managuensis) in her nesting site. Photo by Martin Cabrera.

All cichlid fishes in Nicaragua provide extensive parental care to their fry for the first several weeks after they hatch. There is fierce competition among the Jaguar cichlids for high-quality breeding sites such as this one in our photographs. This site is actually a cave under a large rock, with openings on both ends. The male parent of this nest has little or no continued relation with the nest, however. Big male P. managuensis are scarce, and the males tend to abandon nests earlier than the female, in contrast with many other Nicaraguan cichlids. Big males are easily harpooned when on nest, and unscrupulous SCUBA divers often harvest this fish, as a trophy and for a great meal.

This female is emaciated from the physical stress and reduced food intake associated with reproduction. Photo by Martin Cabrera.

Fry feed on detritus and phytoplankton/zooplankton. They stay close to their fellow fry at all times, depending on the maxim safety in numbers. Among the most dangerous predators of cichlid fry are the Bigmouth Sleepers (Gobiomorus dormitor), introduced into Lake Apoyo only 22 years ago. Both adults and juveniles can catch cichlid fry, especially when a single fish has separated from the group. Fry face a much greater risk of capture when separated from their siblings.

Mother P. managuensis and her fry in Lake Apoyo, Nicaragua. Photo by Martin Cabrera.

We at FUNDECI/GAIA are working to determine the population structure of the fishes, plants and other life in Lake Apoyo, Nicaragua. This delicate lake is under tremendous pressure from people who want to do things that affect the lake: fish unsustainably, cultivate agricultural products using agrochemicals, build houses and install grassy gardens which use copious quantities of water and leave pollution in the lake. With a population baseline, we can determine variations in populations of the different fishes and plants which may result from human-induced alterations in the lake.

This female guapote barcino tends to thousands of fry. Photo by Martin Cabrera.

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Bird Studies in Nicaragua

Anyone who has done some birdwatching in Nicaragua knows there are some great birds in this country. Observing birds by binoculars, however, still leaves many details unseen, as the photos below can demonstrate. We get a special opportunity to observe birds up close when mist netting. There are few tasks as gratifying as one involving the observation of a living, wild bird up close, especially our birds here.

Leslie patiently waits for this Blue-tailed Hummingbird (Amazilia cyanura) to fly away. Photo by Emily Williams.

By studying the birds in Laguna de Apoyo Nature Reserve, we are learning about bird communities in the Nicaraguan tropical dry forest habitat that dominates the terrestrial areas in this protected area. We are also learning, however, about land use, by determining which birds are found in different areas according to the human activities in each. Some birds can use only good forest habitats, and they may be getting forced out by forest degradation. We are hoping to demonstrate consistent patterns in bird populations according to land use and to the changing forest structure as a reforested area grows back into a relatively mature, natural forest.

A Yellow-throated Vireo (Vireo flavifrons) wants to make his disagreement known. Photo by Emily Williams.

At least 225 bird species have been documented in Laguna de Apoyo Nature Reserve, to date. Mist netting has helped us confirm several species which had been poorly documented by sightings. Many of the birds captured during mist netting, in appropriate season, are migratory birds, such as the Yellow-throated Vireo (Vireo flavifrons) and the Painted Bunting (Passerina ciris). Perhaps a quarter of the species found in Laguna de Apoyo Nature Reserve are migratory. Almost all migratory birds here nest further north and spend the non-breeding season here.

The male Painted Bunting (Passerina ciris) has dramatic coloration. Photo by Emily Williams.

Some migratory birds winter in mixed-sex flocks, and others segregate by sex and/or age in their southern, nonbreeding range. By counting the birds by sex and age in Laguna de Apoyo, we can help to determine migration patterns for these birds. Appropriate habitat is required for all migratory birds, especially the Red-Listed species such as the Painted Bunting (Near Threatened), and for all sexes and age classes.

Painted Bunting males are bright, whereas the females are drab. Photo by Emily Williams.

Even when the migratory birds have returned to their nesting ranges, the forests and shoreline of Laguna de Apoyo Nature Reserve continue to be conspicuously occupied with birds. The year-round resident birds, which will have become even more evident when the migratory birds have gone, may even reproduce during the stay of most migratory birds, during winter in the northern hemisphere.

The White-tipped Dove (Leptotila verreauxi) is among the larger species we catch commonly in mist netting activities in Laguna de Apoyo Nature Reserve. Photo by Emily Williams.

Not all birds use the same resources, of course. Many resident birds avoid areas with certain kinds of human impacts, such as the elimination of large, old trees, or the clearing of ground cover. The White-tipped Dove (Leptotila verreauxi) is an example. It is common in forest, but quite uncommon in yards, even where the yards have large, old trees. Another resident bird which is affected by human activity is the Northern Barred Woodcreeper (Lepidocolaptes sanctithomae). This species is common on the south side of Lake Apoyo, but absent from the north side, where greater human impacts are found on the vegetation structure. 

The Northern Barred Woodcreeper (Dendrocolaptes sanctithomae) is not well-documented west of Lake Nicaragua. Photo by Emily Williams.

Some of the local people brand us as tree-huggers, which is fine by us. We seem to get in the way of some people who have big plans for building inside the Laguna de Apoyo Nature Reserve, and they would rather that we go away. That gives us even more motivation to continue to work to save the forest and lake of this reserve. The greatest aspect of our bird studies is that of the people-those who are dedicated and even thrilled by the birds, and learn along the way. Our conservation science interns and volunteers bring life to our projects.

Work as a volunteer in wildlife monitoring is exhausting but worthwhile. Photo by Emily Williams.

The most thrilling of the birds we catch with mist nets must be the most demanding for our technicians, the hummingbirds. They are the smallest and, by far, the most delicate of the birds we catch. Hummingbirds keep very little "reserve" to fuel their activities, requiring that they feed and drink often. We give the hummingbirds water when they are captured, and we process them as quickly as possible to allow them to resume their activities with little interruption. Hummingbirds are usually docile in the hand, and sometimes won't fly away immediately when released.

Hummingbirds are not easy to see well when on the wing, so having one in the hand is particularly special. One can appreciate so many particular features of these birds when they are still and close.
With all the information we gather, we are trying to find which birds are segregated by land use and what can be done about it. We are looking for clear recommendations to promote the entire reserve as good forest and lakeshore for the birds.

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