(Research conducted in collaboration with the Institute of Tropical Forestry, Southern Forest Experiment Station, U.S. Forest Service.)
By James W. Wiley
Puerto Rico Field Station
Patuxent Wildlife Research Center,
U.S. Fish and Wildlife Service,
The Puerto Rican parrot (Amazons vittata) was once abundant throughout Puerto Rico and on at least 3 of its 4 satellites. Within 500 years of Columbus’ “discovery” of the West Indies, the species had plummeted to the edge of extinction with only 13 birds left in the wild by 1975. Many complex factors and events have figured in the species’ decline. Habitat loss was an obvious cause (Snyder 1977, Wiley 1980), however, several other, more subtle factors became increasingly important as populations dwindled. It has taken a team of biologists many years to determine the sources of the parrot’s problems and to develop techniques for reversing the decline (Wiley 1980, Snyder et al. ms.). As a result of this research, the wild population has more than doubled in the last 7 years and there is now reason for cautious optimism that the species may yet be saved.
A captive Puerto Rican parrot research program has been essential in the recovery of the species. In this paper are described some aspects of the captive program and how it forms an integral part of the research and management of the wild Puerto Rican parrot population.
THE CAPTIVE PROGRAM
From its inception the Puerto Rican parrot research program has been envisioned as consisting of two components: the study of the wild population, and maintenance of a captive flock. It was planned that these two components be closely integrated, with the captive flock supplying additional parrots for bolstering the existing wild population in the Luquillo Forest and, in the future, for re-establishing populations in other areas in Puerto Rico where the parrot has been extirpated. The captive flock also serves as insurance against a wipeout of the species by a natural catastrophe such as a severe tropical storm or disease.
After population surveys of the wild birds revealed less than 30 parrots in the wild in the late 1960’s, study of the wild population was intensified and an all-out effort to get birds into a captive program was begun. A news media campaign was launched to locate any existing captives in Puerto Rico; the Puerto Rico Zoo was persuaded into contributing their two parrots to the program after many years of non-production (they turned out to be two females), and attempts to trap parrots out of the Luquillo population began. In 1972, two wild parrots were captured but since then, to minimize the impact of removing parrots from the wild, only eggs or chicks have been taken. Between 1973-1975, ten eggs or chicks were transferred from the wild to the aviary. Thereafter, parrots (n=4) were removed only to add new genetic material to the captive flock (which at a minimum of 8 different or partially different family lines now represents all existing breeders in the wild plus some no longer known to survive) or where an egg or chick could not be saved in the wild (e.g., parrot chick heavily infested with larvae of the warble fly Philornis (Neomusca) pici). From 1973-1982, fifteen eggs and chicks have been added to the captive flock of wild nests. Of these, eight would have undoubtedly been lost without intervention.
THE LUQUILLO AVIARY
Currently, all known captive Puerto Rican parrots (n=17) are housed at a facility that serves both as an aviary and a field station for biologists on the project. The two story concrete building is in the heart of the Luquillo Forest for convenience in studying the wild birds and to facilitate manipulations between the wild and captive flocks. The Puerto Rican parrot flock is quartered within the building for security against human vandalism and the tropical storms that threaten the island yearly. Af lockof Hispaniolan parrots (Amazons ventralis) is maintained in an aviary annexed to the main building. The field station has facilities for incubation and brooding, food storage and preparation, and isolation and treatment of sick birds, as well as a well equipped wood and metal working shop and apartments for staff.
The proximity of the field station/aviary to the wild parrot population has been vital in handling emergencies and other situations often encountered. Damaged eggs, eggs salvaged from wild nests where cavities have become excessively wet, or where the nest has been threatened by predators (e.g., rats Rattus rattus, pearly eyed thrasher Margarops fuscatus) have been maintained in aviary incubators or under captives until the nest hollow has been fixed, the predator threat thwarted, or egg repaired. Chicks with injuries, parasite infestations, or feather damage have been treated at the field station until their condition has been corrected then returned to the wild nest.
The field aviary has allowed us to add another dimension to our work with the wild parrot population: the employment of a surrogate species in preventing wild Puerto Rican parrot nest failures, a technique that will be explained in more detail later.
THE USE OF SURROGATES
The strategy of employing surrogates or “guinea pigs” places yet another step in the recovery program for the Puerto Rican parrot and may mean a slowed, more cautious progress. However, by experimenting on a more common species before attempting a procedure on a very endangered parrot, we have avoided mistakes that would have not just delayed the program but would have set it back. Uses we have made of Hispaniolan parrot surrogates include: 1) medication dosages, surgical procedures, and anaesthetic techniques, 2) correct temperatures for artificial incubation of eggs and brooding of chicks, 3) diet, 4) marking for identification, 5) sexing techniques, 6) training hand-raised chicks before placing them into wild nests, 7) fostering eggs and chicks, and 8) release techniques for free-flying birds. Some of these uses will be described more fully below.
The native Taino Indians kept Puerto Rican parrots as pets before Columbus’ visits to the West Indies. The species was a common pet among European colonists on the island and in the 19th century Puerto Rican parrots were well-known in the European pet trade (Russ 1895: 110-111) and probably in zoological collections. Still, there are no records of its breeding in captivity. We, therefore, have had to build our captive program on techniques modified from successful programs for other parrot species.
Between 1970 and 1982, 10 female Puerto Rican parrots have laid eggs, although only 2 of these females have produced fertile ones. A number of events and problems have contributed to the low rate of fertility among pairs (Wiley 1980, Snyder et al. ms.). Puerto Rican parrots are not sexually dimorphic and we have had to rely upon other means for sexing the captives. Early attempts using a karyotyping method resulted in some mis-sexings and subsequent formation of homosexual pair bonds. Thereafter we tried steroid analysis, a then new technique developed by Arden Bercovitz and his co-workers at the San Diego Zoo (Erb and Bercovitz 1980). This method has proven accurate for birds older than one year.
All captives have been randomly taken from the wild; i.e., we did not know the sex of individuals taken as eggs or chicks. Nevertheless, the captive flock’s sex ratio has been strongly biased toward females, resulting in insufficient males to form heterosexual pairs. With the addition of more males to the flock in the last few years, that bias is now somewhat less (6 males: 8 females) and the aviary presently has 6 heterosexual pairs of Puerto Rican parrots.
Behavioral problems of the captives may have led to poor pair bonding. A wild-caught male has not accepted a mate, which is perhaps related to his timidness and aversion to the captive environment. Although we have made efforts to avoid such associations, several hand-raised captives have become imprinted on humans. Some of these attachments are broken after the birds have been established in pairs, but other individuals prefer a relationship with their human handlers probably at the expense of a productive pair bond with their cage mate.
The first fertile Puerto Rican parrot eggs were produced in 1978. Those eggs failed to hatch but each year since we have fledged chicks from the captive flock. Thirty percent (26 of 88) of the eggs produced by heterosexual pairs (n=7) have been fertile. The 2 pairs that have produced fertile eggs have had a fertility rate of 68 percent of eggs laid. Fifty percent of the fertile eggs have hatched and 38 percent have produced fledglings. Seven of the 10 captive-produced chicks have been fostered into wild nests and 3 have been retained in the captive flock.
EXPERIMENTS TO INCREASE EGG PRODUCTION
Since the program began in 1968 we have twice observed wild Puerto Rican parrots produce a replacement clutch after their first clutch was lost. Encouraged by these observations, in 1980 we performed a forced replacement experiment on a wild parrot pair that had been laying thin-shelled eggs for several years. Some of these had been salvaged by repairing thin areas and cracks in the shells. With the onset of breeding season we had also been provisioning the nest with calcium blocks which the female ingested resulting in her last-laid eggs being thicker-shelled (yet still thinner than normal). By inducing the female to lay a second clutch we hoped she would produce more eggs and, because she would have more time to ingest the provided calcium, the later-laid eggs would be thicker-shelled. We removed the pair’s thin-shelled clutch (4 eggs) and the female replaced it with a clutch of 2 eggs, both of which were fertile and thicker-shelled.
Although this technique has obvious value for increasing productivity of the wild population, we know from observations of parrots nesting in the wild it also has an inherent danger in that, rather than recycle after the first clutch ist aken,the pair may shift from an optimal nest site to some other, lower quality site or forego breeding altogether for the year. Nevertheless, in certain cases, and used with care, this technique does appear fruitful for management of the wild population.
Based on these observations and experiments on recycling in the wild population we tried double-clutching experiments on captive Hispaniolan, then Puerto Rican, parrots. We removed the entire clutch, allowing the females to replace it with an additional clutch. Double-clutching experiments have been preformed 4 times with captive Hispaniolan parrots and 7 times with Puerto Rican parrot captives (Table 1). Although the number of eggs in first and second clutches were no different from the number of eggs in unmanipulated clutches (P>0.05 for both species; t-test), there were fewer eggs laid in the second set than in the first set in double clutches (Puerto Rican parrot: x+s.e.first= 3.0+O vs. xsecond7= 2.3+0.4; P<0.05). Hispaniolan parrot: xfirst= 4.5+0.3 vs. xsecond=3.5+0.3; P<0.05). The total number of eggs laid by double-clutched females was greater than that laid in unmainipulated clutches (Puerto Rican parrot: xunmanipulated= 2.9+0.3 vs. xdoubled= 5.3+0.4; P<0.001). (Hispaniolan parrot: xunmanipulated=3.7+0.3 vs. xdoubled= 8.0+0.6; P<0.001). In 1981 and 1982, we conducted a series of experiments to test another technique for increasing egg production. Hispaniolan and Puerto Rican parrots are indeterminant layers so that by removing each egg as it is laid, leaving the nest empty, the captives will continue to replace the eggs, usually to a total greater than that achieved through simple replacement of whole clutches (Table 1). The technique was first attempted on captive Hispaniolan parrots, one of which produced 21 eggs before we stopped the experiment. Again, the sequential removal technique yielded more eggs than unmanipulated clutches (xunmanipulated= 3.7+0.3 VS. Xsequential= 12.5+0.3; P<0.01), although the number produced by this method was not significantly greater than that produced in double clutches (xdouble= 8.0+0.6; P>0.05).
After these experiments, we attempted the technique on captive Puerto Rican parrots, with the same success (Table 1). Puerto Rican parrot egg production increased an average of 179 percent over unmanipulated clutches (xunmanipulated= 2.9+0.3 vs. xsequential= 8.1 +1.1; P<0.001) and 53 percent above the number of eggs produced by double clutching (x5.2+0.4; P>0.05).
Fertility was unaffected by the manipulations (Table 2). Hispaniolan parrot eggs from unmanipulated clutches (xfertility= 89.4%) did not differ from that of eggs in doubled clutches (x = 93.8%; P>0.05) or eggs sequentially removed (x=85.8%; P>0.05). Similarly, unmanipulated clutches of Puerto Rican parrots (xferti I ity= 58.3%) did not differ from that of eggs in doubled clutches (x = 77.3%; P>0.05) or sequential removal (x = 72.5%; P>0.05) clutches. Fertility of eggs produced during double-clutching experiments did not differ from that of eggs from sequential production for either species (P>0.05). In sequential clutches Puerto Rican parrots did show a decline in fertility in later-laid vs earlier-laid eggs (P<0.001). Unmanipulated Puerto Rican parrot clutches and all classes of Hispaniolan parrot clutches had no difference in fertility between early-and late-laid eggs. In addition to the obvious value of increasing the number of eggs, the sequential removal technique has other applications. Egglaying may range over 1 to 1'/2 month span within the wild population and initial laying date shows considerable annual variation. Because of their more controlled environment, the captive parrots' breeding activity may not be cued on the same controls as the wild population during any one year and egglaying may be quite out of phase with the wild pairs. Synchrony between the wild captive populations is critical in fostering eggs and chicks among nests. In our experiments we led captive Hispaniolan parrots through a series of egg removal manipulations then allowed them to sit on their "final" clutches. Although one of these females had gone through 21/2 months of egglaying by the time she was left with eggs, she still sat on her eggs longer than full-term (normally 27 days) and successfully hatched chicks. From these results we arrived at a procedure wherein captive parrots are "primed" into breeding early (i.e., before the wild pairs) by stimulation with the increased day-length of an artificial photoperiod system. Once egglaying has begun, the captives can be maintained in an "egglaying mode" through the sequential removal of eggs. When the wild population begins egglaying, the activity of the captives can be closely synchronized with the wild birds by permitting the caged birds to sit on their eggs. Switches between the populations can therey be made using like-aged eggs or chicks. ARTIFICIAL INSEMINATION With increased egg production and problems within the captive Puerto Rican parrot flock (e.g., fewer males than females, behavioral abnormalities), an artificial insemination program would seem appropriateto improve fertility. Until 1981 only limited attemptswere madetoutilize this technique. In 1978 George Gee, a biologist with considerable practical experience in artificial insemination techniques, helped us to train 2 Puerto Rican parrot males as semen donors. One male produced minute amounts of viable sperm which was artificially inseminated into his mate. The female later produced fertile eggs, but the male had also begun copulating with her and our fertilization efforts were probably only accessory. We did not further pursue the development of artificial insemination as bonds within those pairs with behavioral problems seemed to be improving and we had high expectations that normal copulation would ensue. By 1981 reproductivity of the flock remained unchanged and we decided to once more try artificial insemination. Gee again visited the field station and made an intensive effort between 17 February and 12 March to train Puerto Rican and Hispaniolan captives and collect parrot semen. Nevertheless, the endeavor failed. Probably because of disturbances to the flock resulting from the attempt to collect semen, 1981 breeding activity in the captive flocks was set back several weeks and some pairs failed to breed altogether. It became obvious that, if we hope to obtain semen for an insemination program, our captive parrots will require an extensive period of conditioning and training which should begin months before the onset of the breeding season. FOSTERING We have used fostering extensively as a management technique both with the wild and captive populations. Eggs or chicks from one nest are temporarily or permanently transferred to another nest for protection against threats or to encourage breeders to re-cycle. There are also other reasons we may foster eggs and chicks into nests: 1) to provide more reliable care, 2) to allow first-time captive breeders a chance to "practice" on a less-valuable surrogate, 3) to "train" hand-raised chicks to accept care by an adult parrot, 4) to maintain a parrot pair's nest activity after its own eggs or chicks are removed, and 5) to bolster the wild population through fostering of captive-produced chicks into wild nests. Fostering in the Aviary We have removed eggs from under first-time captive breeders when we were uncertain whether the pair would display proper nest attentiveness. Such eggs were artificially incubated or fostered under reliable Hispaniolan or Puerto Rican parrot females. More recently we have taken eggs from captive nests to encourage the adults to re-cycle in double-clutching or sequential removal manipulations. Eggs removed may be replaced with Hispaniolan parrot eggs or plaster or epoxy-covered wooden dummy eggs. We have not allowed Puerto Rican parrots breeding for the first time to raise their own chicks. Rather we have let them "practice" at being parents with Hispaniolan parrot chicks. Once they have proven their proficiency the adults are permitted to raise their own offspring. Artificial incubation is extensively used in the parrot program fora number of reasons: 1) to care for wild-produced eggs that have been salvaged after adults have abandoned them or where a nest is in danger of failing, 2) to provide abnormally high humidity needed to circumvent excessive moisture loss from thin-shelled eggs, 3) as insurance against egg chilling through abandonment by a first-time captive breeder or a proven poor sitter, and 4) to increase captive egg production through forced renesting. Parrot chicks are hand-raised for some of the same reasons mentioned for artificial incubation. Several of the Puerto Rican parrot chicks destined for placement in a wild nest have been hand-raised. Hand-raised chicks may initially be inept at taking food from an adult parrot. This poor coordination between adult and chick may disquiet an adult and further delay feedings of the nestling. To condition hand-raised nestlings to properly interact with adults, several days before transfer to a wild nest we place the chick with an adult captive Hispaniolan or Puerto Rican parrot. This contact allows the chick to become skilled in taking food from an adult and such "trained" chicks are more quickly accepted by wild adults than untrained chicks. Fostering in the Wild We have added captive-produced Puerto Rican parrot chicks to wild nests to augment production by the wild population. Such captive-produced fosters have been used to replace a clutch or brood lost at a wild nest or to bolster the brood size at an active nest. In experiments conducted at 2 wild Puerto Rican parrot nests we learned that the normal brood size of 3 chicks can be artificially increased to 4 with no apparent negative effect on chick growth, development, or fledging success. Manipulation of eggs and chicks in wild nests has become a regular strategy in the Puerto Rican parrot recovery program. Every effort is made to keep nests active, as a nest failure one year could cause a pair to abandon that site for the next year's breeding effort. Each year between 1969 and 1979 one wild pair ("South Fork") consistently changed its nest site after failing to fledge chicks whereas the pair reused the same nest in the years following successful breeding seasons. There are few adequate natural nest sites in the parrots' range (Snyder 1977, Wiley 1980) and abandonment of a suitable site might result in the pair adopting a suboptimal site in subsequent years. Thus, when problems arise, we have attempted to retain a pair's interest in the optimal site by manipulating nest contents. When it is necessary to transfer eggs from wild nests to the field station, dummy eggs are substituted rather than risk moving real eggs from the aviary or another wild nest through the forest to the nest in need. Puerto Rican parrots will sit on eggs several days beyond the normal incubation period. Therefore, a wild chick hatched at the aviary can be kept under observation at the field station for 3-7 days before replacing it in the wild nest. This gives us the opportunity to determine that the chick is in good health, and has the further advantage of the chick being older and better able to comfortably withstand its return trip to the wild nest from the field station. If difficulties occur during the brooding period we have made switches of like-aged chicks from other wild nests or from chicks produced by the captive Puerto Rican flock. If the problem is such that the resident chick cannot be replaced in the nest at a reasonable age it may be shifted to another wild nest, if one is available, or retained in captivity and the fosters allowed to fledge. Some of the manipulations become quite complicated; e.g., situations that require simultaneous switches at 2 or 3 nests. Before we had the Hispaniolan parrot flock or the captive Puerto Rican parrots began producing chicks, switches could only be made by transferring chicks from one wild nest to another. At times there were no chicks of the appropriate age. At other times, when it was necessary to remove whole broods of 3 chicks from a nest, we had only one chick to foster into the nest. After the problem was corrected we reversed the switch, going from one chick back to the 3 resident nestlings. Adult parrots show little reluctance in accepting these switches during the nestling period provided the exchange is not made the last 2 weeks before fledging. Within that time span we found there was difficulty in fostering alien chicks into these nests although once the resident chicks were replaced they were accepted. Probably there was some communication process by then that allowed adult recognition of the alien chick(s) as not their own. In cases we judge too dangerous to permit Puerto Rican chicks to remain in the nest, we have used captive-produced Hispaniolan chicks to bear the brunt of the danger until the threat has passed, at which time the Puerto Rican chicks are replaced in the nest. Hispaniolan chicks therefore serve as "stand-ins" to maintain adult Puerto Rican parrot interest in the nest. For example, a wild Puerto Rican parrot pair laid a thin-shelled clutch in 1979. Since it had laid far earlier than other wild pairs or any of the captive Puerto Rican parrots, we had no Puerto Rican chicks to foster into the nest to keep the adults' interest after the eggs went beyond full-term incubation without hatching. Fortunately, a pair of captive Hispaniolan parrots had laid just after the wild Puerto Rican pair. When the wild pair showed signs of desertion, we prematurely force-hatched a Hispaniolan chick (something we would not have chanced with a Puerto Rican chick) and exchanged the still-wet nestling for the dummy eggs in the nest. The chick was immediately accepted (the female barely left the nest for several days) and held the nest active until a Puerto Rican chick was avaialble to substitute into the nest. In another situation, the resident adult female was injured and failed to return to the nest area for several days during which time the male had to intermittently brood the small chick and alternately forage for periods of up to 2-3 hours, thereby leaving the chick uncovered. Rather than risk losing the chick to chilling or predation, we substituted a similar-aged Hispaniolan parrot chick into the nest. We had to supplementally feed and occasionally warm the chick in the male's absence as the female was still missing and he was unable to care for it normally. Later in the season a pair of non-nesting Puerto Rican parrots moved into the residents' territory and took over the nest site. The resident male was only able to sneak into the nest to feed and cover the chick during those periods when the aliens were engaged in other activities, resulting in further degredation of the chick's care. There was no way we could justify replacing the resident Puerto Rican chick into the nest, but we maintained the nest active through the worsening crisis and the pair returned to the site to breed the following season. We have used breeding pairs of captive Hispaniolan parrots in experiments to determine how far we could go with manipulations of nest contents. In one trial, a female Hispaniolan parrot housed with an immature male was led through a series of manipulations wherein she first brooded her own infertile eggs, then a series of replacement eggs from captive Puerto Rican and Hispaniolan parrots and also wild Puerto Rican parrots. Because she was regressed through younger and younger eggs, the female sat on eggs much longer than the normal incubation period. She was eventually allowed to hatch chicks (eggs pipped under her but were removed to an incubator for hatching) and permitted to raise nestlings. She was progressed and regressed through several ages of Puerto Rican and Hispaniolan chicks from various sources but finally experienced a 33 day spurt in development when we replaced a 34 day old chick with a 67 day old one that fledged the following day. Still the female maintained excellent care of all eggs and chicks throughout the 8 switches. Although we do not anticipate having to perform such extensive manipulations on wild parrots it is reassuring to know the extent to which parrots can be pressed. RELEASE OF FREE-FLYING BIRDS A high priority of the Puerto Rican parrot recovery program is to find ways to release free-flying birds. As there are only from 3 to 4 wild Puerto Rican parrot pairs nesting each year we have already experienced the problem of having more chicks produced by captive pairs than there were nests available in the wild for fostering and we have been left with no sensible alternative other than retaining these "excess" young in captivity. Furthermore, we eventually plan to re-establish Puerto Rican parrot populations in areas of Puerto Rico where the species formerly occurred. This will entail the release of captive-produced chicks where no nesting birds exist and thus no opportunity for fostering. It follows then that before release of free-flying Puerto Rican parrots can be made in either the Luquillo Forest or other parts of Puerto Rico there is need to develop techniques that achieve an acceptable survival rate and produce birds that become a part of the wild population. .In 1982 we performed experimental releases of captive-raised Hispaniolan parrots in southwestern Dominican Republic. Ourstudy area was in a mountainous region still inhabited by populations of wild Hispaniolan parrots. Birds for the experiments were from 2 sources: 23 were raised at the Puerto Rico Field Station aviary, and 13 were donated by the Parque Zoologico Nacional ("Zoodom") in Santo Domingo, Dominican Republic. All of the Puerto Rico Field Station birds and most of the Zoodom parrots were at least partially hand-raised. The birds ranged in age from fledglings to 5 years old; age classes were equally represented in the experimental groups. Parrots were released in 2 experimental groups (18 birds per group): non-conditioned birds and pre-conditioned birds. Before release the non-conditioned parrots were maintained in an aviary at the study site. They were supplied prepared foods similar to those to which they were accustomed in captivity and were not provided with natural foods from the area. After 3 to 6 days they were carried in windowless boxes to an unfamiliar site, distant from the field aviary, and force-released as a group. These birds were not given the option of returning to a field aviary for shelter nor were they subsidized for food. The pre-conditioned birds in the second group were held in a field aviary in full view of the eventual release area. We supplemented their accustomed prepared foods with fruits and seeds naturally occurring in the area to give the birds experience in identifying and handling native foods. After 9 to 12 days of conditioning the birds were allowed to leave the field aviary at will. They could return to the structure for shelter, and food and water, which we provided daily. This group was gradually weaned from human-supplied foods as they began foraging in the surrounding forest. All birds wore plastic wing tags that were color coded to release group and individually coded with symbols and numbers. In addition, 18 birds (9 birds per release group) were fitted with radio transmitter collars. Movements and activities were monitored from 3 lookout towers in emergent trees on hillsides overlooking the release valleys as well as from several ground stations throughout the areas. Behavior of the birds in the 2 groups was dramatically different. The non-conditioned parrots dispersed immediately from the release site, displayed little flock cohesion, and demonstrated aberrant foraging behavior. Several recaptured parrots had lost considerable body weight; by day 7 after release, 6 birds in this group had lost an average of 48.0+8.4 g (17.9% of pre release body weight). There was no difference in survival among age classes at day 5 after release (X'=3.260, d.f. = 4, P>0.05) and day 13 (X2 = 2.965, d.f. = P>0.05), although sample size was small.
In contrast, the pre-conditioned birds displayed good flock cohesion, normal feeding behavior, and no immediate dispersal. The group members had a high survival rate and eventually integrated into wild parrot populations. As in the non-conditioned group, there was no difference in survival among age classes (X2 = 0.178 for day 25, X2 = 1.448 for day 55; both P>0.05, d.f. = 3).
Although these results are preliminary, they are encouraging and suggest that controlled releases of captive-produced parrots can yield acceptable numbers of birds that will survive and integrate well into the wild environment.
Future research goals of the Puerto Rican parrot program include: 1) development and incorporation of an artificial insemination program for the captive flock, 2) further refinement of release methods, and 3) development of remote monitoring techniques.
Workable methods of obtaining viable semen from captive Amazona parrots will be determined, first using Hispaniolan parrots. Once suitable methods are developed we will incorporate an artificial insemination program into the Puerto Rican parrot propagation project. By inseminating the extra females and females of infertile pairs a substantial rise in fertility among the captives is anticipated.
We will be continuing the experiments on release of captive-raised parrots. A primary objective is to achieve release techniques that minimize parrot association with humans; i.e., methods of raising and handling chicks to obviate problems of post-release association with humans. We will investigate the use of aversion training to dissociate parrots from humans and also in developing parrot avoidance responses to other predators.
Further work will be conducted toward devising a suitable telemetry package for use on free-flying parrots, especially an attachment method reliable enough to withstand the rejection attempts by parrots but allowing the transmitter to drop off the bird after it has served its purpose. Techniques of monitoring radio-tagged parrots from fixed and mobile stations in the dense, montane rainforest of the Luquillo Mountains are to be improved.
Erb, L., and A.B. Bercovitz. 1980. Fecal steroid analysis: non-disruptive technique for psittacine encocrine studies. pp. 65-77.
In R. F. Pasquier (ed.) Conservation of New World parrots. Int. Council Birds Pres. Tech. Bull. No. 1.
Russ, K. 1895. The speaking parrots: a scientific manual. L. Upcott Gill, London.
Snyder, N.F.R. 1977. Puerto Rican parrots and nest-site scarcity. pp. 47-53. In S.A. Temple (ed.) Endangered birds–Management techniques for preserving threatened species. Univ. Wisconsin, Maidson.
Snyder, N.F.R., J.W. Wiley, and C.B. Kepler. Ms. The parrots of Luquillo.
Wiley, J.W. 1980. The Puerto Rican amazon (Amazons vittata): its decline and the program for its conservation pp. 133-159. In R. F. Pasquier (ed.) Conservation of New World parrots. Int. Council Bird Pres. Tech. Bull. No. 1.