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The breeding of caiques has only become a reliable proposition within the last twenty years. This is primarily due to the development of reliable methods for sexual identification in the early 1980’s. Additional reasons are a better understanding of their husbandry, less reliance on wild caught stock, and what may be an on going process of selecting for birds that breed better in captivity. Here I combine my own experience with those of a number of earlier breeders to help guide those wishing to breed caiques.
A. Securing breeding stock.
The biggest challenge for breeders is securing breeding stock, especially if you plan to set up more than two or three pairs. Before import restrictions were imposed in 1993, “wild-caught” caiques, particularly black-headed caiques, were regularly imported into the United States . Although caiques were never imported in great numbers, there was a steady supply. At that time if you wanted to set up breeding pairs you contacted an importer and arranged a purchase of a few birds at a nominal price of $200 and often less per bird. The reason for the low price was that these new imports usually did not make good pets. In some places in the world, particularly Europe and parts of Southeast Asia , imported birds may still be obtained since Guyana still exports a few black-headed caiques. Now though, breeders in the United States and places like Australia, where caiques are extremely rare and expensive, must rely primarily on domestically bred birds as a source of breeding stock. Fortunately, early caique breeders in the United States and Europe had considerable success. The result has been the development of good husbandry practices and a larger supply of domestically reared birds. Hopefully the breeding of caiques is well enough established in the United States and other parts of the world that there will never be a need to import the large numbers wild caught stock that allowed us to establish the commonly bred subspecies in captivity.
As noted though, only two subspecies of caiques are well established in the United States—the black-headed (P. m. melanocephalus) and the yellow-thighed (P. l. xanthomerius). In Europe, Brazil and some other parts of the world, the green-thighed (P. l. leucogaster) is being bred. To my knowledge, the breeding of the yellow-tailed caique (P. l. xanthrus) has been limited to Brazil , and I am unaware of anyone currently breeding the pallid caique (P. m. palidus). One breeding of these subspecies has been restricted are the CITES and national government regulations related to exporting and importing of birds. The reason we have such a good supply of the black-headed and yellow-thighed subspecies is that a fair number of them were imported before the imposition of the 1993 legislation in the United States. There still are wild-caught pairs of the black-headed caiques producing chicks in the United States, but most of the producing yellow-thighed pairs are now domestically bred. There is great interest in introducing the green-thighed subspecies in the United States, but there are only a few breeding them now. There are a few birds exhibiting the green-thigh phenotype in the United States but they are of questionable lineage. Some of these birds are descended from the inter-breeding of the green-thighed with the yellow thighed at Busch Gardens at the Tampa. In the 1970’s, the breeding of any caiques was considered a triumph, but this has introduced the problem of the certainty of their lineage. Better documented stock is now arriving from Europe and other parts of the world. I also understand that they may once again be imported from Brazil because that country allows the export of birds that have been bred in captivity. I suspect eventually, all the subspecies will be established in aviculture, but it is going to be awhile before you can buy a yellow-tailed, a pallid, or even a green-thighed as a pet.
Presently most of the breeding stock is captive bred, obtained from the progeny of your own pairs or from other breeders. Even so, you should take great care when obtaining new stock. Occasionally, you see advertisements listing proven breeders for sale. The term “proven breeder” only means that the pair has laid a clutch of eggs sometime in the past. So, when you see such an ad, you must ask yourself why anyone would sell birds that are producing two or more clutches of chicks a year worth thousands of dollars. If you elect to purchase them, you may be taking on someone else’s problem. You need to ask lots of questions such do the birds destroy their eggs right after they are laid? Has the pair killed its newly hatched chicks? Are the birds getting so old that they are no longer suitable for breeding? Are they suffering from disease? Are they poor producers? Are they in good condition and of good quality? If you elect to purchase such birds, you need to assure yourself that the reason seller is disposing of them is genuine. Sometimes you get a good deal and one regularly hears of the purchase of a previously unproductive pair that starts producing after they settled into their new regime and environment. However, you need to realize there are certain risks with acquiring adult pairs.
For the novice with patience, the best approach is to purchase young birds and pair them up yourself. Both hand-reared and parent-reared birds make good breeders. The only proviso is that they not be too closely related. One way to set up pairs is to purchase birds at the prevailing retail rates. If you want to purchase two or more birds, more reasonable prices may often be negotiated when you purchase them directly from a breeder. When you do this, buy from at least two different breeders so as not to perpetuate in-breeding. Always request as much information about each bird’s heritage as possible. One suggestion that may save money is to buy parent-reared birds if available. Some breeders allow a few chicks to be parent-reared with the intention of using them as future breeding stock. These do not make good pets, but this does not matter if you intend to breed them. The disadvantage of purchasing young stock is that you will have to wait the two to three years before the birds reach maturity and endure their first awkward breeding attempts before they settle into being reliable breeders.
After obtaining new breeding stock, it is very important to ascertain that the birds are in good health and unlikely to transmit disease to the rest of your flock. So it is very important for new birds to receive a veterinary health examination. As a general rule, the more birds you already own, the more concerned you need to be about introducing new birds. Do not accept the word of the seller no matter how reliable they seem to be; have your own examination done by an avian veterinary specialist. You will also need to keep the birds quarantined from your other birds for at least 45 days while you await results of veterinary assays and the emergence of possible diseases resulting from the stress of relocation.
B. Setting up new breeding pairs.
There are three requirements for birds to breed and one strong recommendation. The requirements are that they must have reached sexual maturity, the pair must be comprised of birds of the opposite sex, and they must be compatible with one another. The strong recommendation is that the birds be unrelated. The recommendation is made with the intent of retaining the genetic vigor of the population, but should be put aside should the goal be to increase the number of individuals bearing a desired new mutation.
The generally accepted age when caiques reach sexually maturity is three years. Some domestically bred birds will breed at two years and the earliest reported age is eleven months (Lima, 1996), but do not expect them to be good parents (Ireland, 1988). The onset of sexual maturity of female caiques is more obvious for males. If you have other birds breeding in their vicinity, they sometimes become irritable. If they are hand tame, they may inexplicably bite you. If they are not tame, they may become more aggressive when you go to refresh their food and water.
Although is seems obvious that the birds must be of opposite sex, the fact that caiques are monomorphic presents a challenge. The only reliable and reasonable methods for sexing caiques are by surgery or by a DNA method. Prior to the advent of surgical sexing, Tom Ireland (1988) set up three pairs based on head and body shape, vent size, and compatibility. They failed to produce. After surgical sexing became available, he discovered that he only had two females and, by happenstance, he had placed them in the same cage thinking they were a heterosexual pair. All the pairs he had set up were very compatible with each other. In the case of the female-female pair, one of the birds took on the role of the male and the other the female. Once they were separated and re-mated with males they both produced fertile eggs and chicks. Thus, do not make the mistake of thinking you can tell the sex of your birds based on their appearance or behavior. These days, I advise anyone wishing to set up pairs to have their birds DNA sexed as soon as possible after obtaining them, even ones that were sexed before purchase. Reporting errors are uncommon, but they do occur. The cost is minimal, about $20 per bird, and it may save you a barren breeding season.
The most difficult aspect of breeding is finding birds compatible with one another. Caiques, particularly the black-headed caiques, can be very aggressive toward each other, and if you carelessly place them together they may fight ferociously even to the point of one killing the other. The best way to match up pairs is to allow them to mutually select each other. If you obtain a large number of birds at one time, Tom Ireland recommended (1988) putting a single birds in small cages and line them up side-by-side with birds of opposite sex in alternate cages. Take care not to place clutch mates next to each other since they already have a mutual affinity. Then watch. Take note of how the birds relate to each other. If you see two birds sitting as close as their respective cages allow, there is a good chance they will make a good pair. Continue to observe for a couple more days and when you feel confident, place them in the same cage. If they have bonded, they will perch next to each other and allopreen. Allow them to adjust a while longer, watching them to be sure they are compatible. You can expect them to have occasional spats, but these should never reach the point where you think they need to be separated again. Once you feel they are compatible move them into a large breeder cage.
Breeding is more challenging if you plan to set up only one or two pairs as is the case for most hobby breeders. As a hobby breeder, I have found it is easiest to begin with unrelated immature birds that are only one to two years old. Place them in separate cages next to each other well away from your other birds in an unfamiliar place. If you acquire several new birds and you feel comfortable that they are healthy, this may be done during quarantine period. I quarantine my birds with a friend who has no birds in order to avoid bringing disease into my flock. There, in the absence of the sight and sound of other parrots, the two birds usually develop an affinity for one another. If they do, you may allow them together for the rest of the quarantine period before finally placing them in the breeder cage.
The two members of the pair should be introduced to the breeding cage at the same time. This provides a neutral territory. If one bird is kept separately in the breeding cage for a long time, it may become aggressive toward the bird introduced later. If both birds are naïve to the cage, neither will feel that the other is invading its territory. If you have a limited number of cages and must place one bird in the breeder cage before the other, it is usually best to place the hen in the breeder cage first (Hollaway, 1999). Then place the male as close to her cage as possible so that they can see and hear each other without allowing direct contact. If they seem attracted to one another, then introduce the male. This order of introduction is needed because males are usually more aggressive than females and will defend the cage more vigorously than a female. Occasionally, though, the female is the more aggressive bird, and if this is the case then you have to reverse the introduction procedure (Hollaway, 1999). If all goes well, the birds will seek each other’s company within a few days. Often, however, it takes weeks or even longer before the birds accept one another, but do not give up too soon. There are, however, some birds that simply refuse to accept a mate no matter how many you offer. I have encountered this with older hand-reared birds and this appears to be unrelated to their sex.
Pairing up birds does not need to be for life. George Smith (1996, 1990) recommends changing mates after a pair has produced a few clutches as a way to maintain genetic diversity and has done this routinely. He separates the original pair and introduces them to their new prospective mates in cage new to both birds. He indicated that you should arrange it so that they cannot see and more importantly not hear their former mates (Smith, 1990). Apart from the normal squabbling of caiques with their mates, he has noted that they soon adjust and go on to produce clutches.
C. Caging of Breeder Pairs.
Caiques are best set up one pair per cage. This must be done because pairs are usually very aggressive toward other birds during the breeding season. In the early history of captive breeding, colony breeding of caiques was used in places like Busch Gardens, but this only worked well for the slightly less aggressive P. l xanthomerius. One reason for colony breeding then was that caiques could not be reliably sexed, and using the colony method increased the chances that birds of opposite sex were in the same cage. Tom Ireland (Marshall, 1995) used this approach in his early breeding attempts with some success, but he later recommended against it (Ireland, 1988). The success of colony breeding, however, may depend on the size of the aviary. The Bristol Zoo in England set up several pairs of the black-headed caiques in a very large aviary and they bred and reared chicks (Smith, 1991). This type of colonial breeding is encouraged by Reillo and McGovern (2000) who feel captive breeding should occur in social groups. This also is consistent with what Brightsmith (1999) suggests, i.e., that P. l. xanthomerius are cooperative breeders in the wild with all members of a small flock assisting the breeding pair. Yet to achieve success in a small breeder operation, I feel they are best set up one pair per cage. In confirmation of this, Paradise Park (2002) in the United Kingdom had a small flock that was kept together for 15 years that never went to nest. It was only after they were separated into pairs that they produced chicks.
The breeding cage should be larger than for ones intended for pet birds, but they need not be too commodious. Smith (1996) observed that he got better breeding from birds housed in smaller cages than in a large aviary. He attributes this to their habit of living within the tree-canopy and the dense foliage and smaller cages gives them a sense of security similar to their natural environment (Smith, 1991). However, recently Low (2002) recommended a nine meter long cage. The cage sizes used by various breeders are summarized in the attached table. The minimum size listed is 24 inches (60 cm) high, 24 inches (60 cm) wide and 48 (120 cm) inches long. I tend to believe that the larger the cage the better since it allows them more room to fly. Most breeders construct their cages out of galvanized wire mesh preferably galvanized after welding. If the birds are caged outside, it is recommended that you use a small mesh size of 1 inch (2.5 cm) by ½ inch (1.25 cm). This small size mesh helps prevent vermin such as rats, mice and snakes from invading the cage. I house my birds inside where there is less threat of vermin, and use a 2 inch (3 cm) by ½ inch (1.25 cm) mesh, although a larger mesh size would be acceptable.
The early literature indicated that caiques were very sensitive to cold, but this is not completely true. Once acclimated, birds do very well outdoors in England (Low, 1972) and as far north as the Carolinas in the United States. They cannot be kept outdoors much further north since caiques do not have enough down feathers to insulate them well (Smith, 1991). I recommend the suspended cages pioneered by Noegel, especially if the birds are kept outdoors. The floors of these cages may be constructed with the same or smaller mesh as the rest of the cage, and are hung from a support structure so that they are well above the ground—usually at or above eye-level. The wire mesh floor allows the feces and other debris to fall to the ground, or preferably cement pads, for convenient cleaning with a water hose. Cages with the earthen floor can be used since caiques do not dig very much, but they are more difficult to clean. Recently, some breeders have taken to constructing large outer enclosures of regular home screening such as those placed over swimming pools as a way to exclude mosquitoes that carry the West Nile Virus.
Since I live in the northern part of the United States where the temperatures regularly drop below freezing and remain there for long periods, it is impossible to leave my birds outdoors over the winter. I also use the galvanized mesh wire cages, but the floors of my cages are large trays fabricated of galvanized metal and the cages are constructed so that they can be slid in and out of the bottom of the cage. Several companies, such as Corners Inc., fabricate these cages at a reasonable cost. I line these trays with layers of newspaper that can be removed one layer at a time for quick clean up, but they are completely cleaned at least once a week. Since caiques feel most secure on high perches, I set the cages as high I can without compromising my capacity to service them, i.e., at about five feet (1.5 m) off the ground.
Caique cages should be arranged so the birds are in sight of each other. Unlike the Amazons pairs that need a privacy barrier so they are out of sight of other pairs during the breeding season, caiques are stimulated to breed when they see and hear another pair going to nest (Smith, 1996). Those who have several pairs, know that same pair usually leads off the breeding season each year (Ireland, 1988; Rellio, 1998). This suggests that the sight and sound of that pair’s activity stimulates the other pairs (Manning, 1991; Low, 1988a; Low, 1977). For this reason, I set my breeders’ cages side-by-side, so they can see the other pairs. Still, some pairs like to have the nest box entrance hole obscured from the view of other pairs, but this can be accomplished with a partial partition.
You should space the cages a short distance away from each other. Ralph Lima recommends the distance between cages should be at least 3 inches. While this distance is sufficient to prevent pairs in adjacent cages from reaching and harming one another with their beaks, it is not far enough to prevent fresh feces from reaching the adjacent cage. Some caiques defecate with considerable force and the fecal trajectory can reach the adjacent cage. I try to keep my cages at least one foot apart and, if practical, further.
D. The nest box.
Caiques will accept almost any nest box as long as it is of sufficient size and well above the floor of the cage, however if the pair is intent on breeding, even the box’s location may not matter. Once, out of necessity, Smith placed a pair in a small utility room and the pair was so earnest about going to nest they used a small box on the floor. The design and size of the nest boxes used by various breeders is listed in the accompanying table. In the wild, they prefer cavities in the forest canopy such as hollow limbs that are too small for the larger parrots (Brightsmith, 1999). However, there is an intense competition for suitable nesting cavities from other birds and animals, so often they do not have the luxury of staking a claim to an ideal cavity. Nonetheless, there are several factors to consider when selecting a box. Perhaps the most important is that at the beginning of the breeding season, caiques continually work their nest boxes. They chew the box itself as well as rearrange and shove the bedding around and even out of the box. To prevent loss the bedding, you can use a slant, bi-level or inverted boot shaped box in which the bedding is reasonably confined to the deepest part of the box. If one of these boxes is used, the bedding tends to resettle back to lowest point, while in horizontal boxes; the bedding gets pushed to one side and then shoved out the entrance. Occasionally, a pair will not accept the box you have chosen for it. If this is the case, you need to experiment with other box designs until they finally settle in.
The box may be made out of several materials. Wooden ones, especially plywood, are the most common, but suppliers also offer ones made of metal and opaque plastic. Since wooden boxes are the most widely available, sellers offer the greatest selection of size and design. They are also fairly cheap and easy to build, and sometimes it is best to build your own if you need it to fit your particular cage. Be sure that any wood used in its construction has not been chemically treated to prevent rotting or termite infestation. The choice of construction material is more critical if the breeding pair is kept outside. A metal box is probably better for outside than wood. Wood tends to bow and the layers of plywood separate if you did not use plywood suitable for outdoor exposure. Another problem with wooden boxes is that the birds can chew their way out of them. On the other hand, metal boxes conduct heat and cold too well. So if you are using metal boxes line their bottoms with wood to provide some thermal insulation.
Most breeders use untreated pine shavings as the bedding. Other materials that are used include fir chips (Weaver, 1995), pine needles, coconut husks and eucalyptus chips. Early aviculturist sometimes added damp decaying vegetable matter as a way to increase humidity, but we now know this should never be done (Them, 1988). As mentioned above, caiques continually work their boxes—they chew and shove the bedding around and it gets degraded or tossed out of the box. You should try to keep about 3 to 5 inches of bedding in the lowest level of the box. When the birds begin to breed, you need to monitor the bedding level almost daily and add more bedding as needed until the first egg is laid. Once an egg is laid, stop adding any additional bedding because this may bury the eggs. Some parrot breeders “cork” the nest box, i.e. line the nest box with sheets of cork. The idea is that the birds will chew the cork in the same manner they would chew and further excavate a cavity in the wild. Smith (1991) does not add any loose litter at all, but instead screws large chinks of soft wood that the birds can whittle away to form the bedding. Some bird specialty stores sell chinks of coconut husk you can add to the nest box for the birds to chew. While this encourages some species of parrot to breed, I have not found this to be necessary for caiques. Still, I occasionally toss in a hunk of cork into their box. Sheets of clean rough cork, intended for the mounting of orchids and bromeliads, may be obtained from plant supply companies, or you can buy unused corks from a vintners supply house. Other soft woods like balsa, soft pine, etc, will do as long as they have not been chemically treated.
While insect and mite infestations of the nest box are not usually a problem for indoor breeders, they can be if the birds are kept outside. Insects are a major problem for wild parrots in the Amazon region and wild macaw chicks are often lost to parasitic fly larva attacks. This is not a serious problem in North America; nonetheless, insect and lice infestations are a matter for concern. To prevent this, Tom Ireland who kept his breeders outdoors in Florida (1988) recommended mixing in a small amount of Sevin dust with the pine shavings. While he gave a caution to use only the 5% commercial powder, and he did not provide any guidance on the ratio of powder to shavings. I have not explored use of insecticides because I keep all my birds indoors.
The box should be positioned outside the cage and be easily accessible for inspection. Because of the need to inspect them, all nest boxes must have an inspection door. The box should also be placed as high as possible on the cage. Them (1988) and Smith (1971) recommend that the box be situated so that the entrance is in an area with low light. The caique’s preference for darkness led a friend of Them to paint the inside of the box black. He then noted that when given a choice they selected the painted boxes over an unpainted ones. While I have not found it necessary to paint the inside of the box, obscuring the entrance to the box entrance from other birds in the vicinity is advised.
Once the pair sleeps in the box, they are usually comfortable enough to nest in it. Occasionally a pair is reluctant to use a box after it is first hung. Usually this reluctance can be overcome by catching the pair late in the evening before it becomes dark, placing them in the nest box, and sealing the entry hole so they cannot exit. Then, first thing in the morning unseal the hole. One night of forced confinement in the box is usually enough for them to lose their fear (Lima, 1996). I have sometimes had to do this for two nights before they adapted, but this approach is usually very effective.
Cage sizes and nest box shape and sizes used by successful aviculturalists.
(h × w × l) ft
Nest Box Shapea
Nest box sizeb
(h × w × l) in
4 to 8 × 3 to 4 × 4 to 7
11 × 8 × 15
7.9 × 7.9 × 11.8
2 × 2 × 3
2 × 1.5 × 3
6 × 3 × 6
24 × 9 × 9
2 × 2.5 × 2.5
18 × 9 × 10
3 × 3 × 4
16 × 8 × 16
2 × 4 × 5
Boot or horizontal
Boot 24 × 12 × 12
Horizontal 10 × 10 × 24
1.5 × 1.5 × 4
3 × 2 × 6
24 × 12 × 12
2.5 × 2.5 × 6
3 × 3 × 4
24 × 8 × 8
3.5 × 3.5 × 5
Gamma or internal ledge
13 × 11 × 9
3 × 2 to 3 × 3 to 6
Vertical or boot
Vertical 10 × 10 × 22
Boot 12 to 15 × 8 × 14 to 20
10 ft long
8.3 × 8.3 × 15.8
a Shapes are illustrated below by profile. Position of entrance hole is indicated by dark spot. b Only the largest dimension is provided.
E. Food and water for breeders.
Breeding birds have different dietary needs during the course of the breeding season than during the off-season. I begin the dietary change when I first notice that the male is making some serious overtures to the female. In my aviary, this is usually at the end of November and beginning of December. Before formulated pellet diets specifically for breeding became available, I added protein rich foods such as cheese, cooked meat, and cooked egg to their everyday diet. This supplementation with “egg food” was and still is a common practice in the breeding of smaller avian species. Now, with the availability of formulated breeder diets I simply switch from the low protein, low fat maintenance pellets to the high protein, high fat breeder pellets. One thing I have learned, though, is that it is best the stick with the same brand for both the maintenance and breeder pellets. Caiques have a definite preference for some brands over others. Switching to one they do no like as well may drive them to partake less of the new brand and be worse than having left them on the maintenance pellets. If they do not like the new pellets, you will notice that they are more diligent about eating their fresh foods. Caiques seem to accommodate to the switch from maintenance to breeder formulations and back if the same company manufactures them both.
Another thing you must provide at the beginning and through out the breeding season are cuttlebones. You need to keep a supply of these on hand since a female caique can chew through these very quickly. I replace these as soon as I notice they have consumed the one in their cage.
Finally, the feeders and water containers should be arranged so that they can be cleaned and changed without having to enter the cage unduly. When caiques breed, some pairs, particularly recently imported birds, may fiercely attack anyone foolish enough to put their hands in the cage. This does not seem to be as big a problem with domestically bred pairs habituated to their care taker, but even they will attack strangers who haplessly put their hand in or near their cage. I provide each of my pairs with a bowl of water for both drinking and bathing. I avoid using the Lixit type water bottles for my breeders because of their tendency to get clogged. A continuous source of water is especially important in warm areas such as Florida. It is also important to monitor their water bowls and keep them filled since the birds often empty a bowl with their exuberant bathing. In large breeding operations, the automatic watering systems that flush and change the water on a regular schedule are indispensable.
F. Mating behavior
Once a pair is comfortable with each other, hopefully they will mate. Breeding is seasonal and appears to be related to day length (Smith, 1991). In the northern hemisphere caiques usually begin to breed from December through about May. However, artificial lighting can abrogate seasonality. In the lull between breeding seasons, the birds are generally less aggressive toward you and other birds. An increase in aggressiveness usually heralds the new season. The females start chewing on their cuttlebone, and the male begins making overtures to the female. The characteristic courtship ritual consists of regurgitive feeding, mutual preening, and maintaining close proximity. Both birds spend a great deal of time sitting touching each other with their tails crossed (Smith, 1971). Smith (1971) also noted that a receptive female often keeps her beak slightly ajar even though she is capable closing it completely As the season progresses, the male usually gets more and more aggressive toward the female, often chasing her around the cage. This is one reason for providing a fairly large cage. He will try all sorts of devices to induce the female to mate with him. One tactic the male sometimes uses to elicit responsiveness is to take on the role of the female and try to squeeze under the female in a sort of reversal of roles.
Pairs tend to be quarrelsome. They often fight over food, which should sit on what perch, and other simple matters. This is normal behavior, but during the breeding season an overly aggressive male is cause for concern. Every pair must be watched closely once breeding commences. Males may try to forcibly feed the hen causing damage in the hen’s beak area (Lima, 1996). More commonly, the male will try to forcibly copulate with the hen. The male can be relentless in his pursuit, often chasing the hen about the cage. If this behavior becomes too violent, you must separate them as soon as possible. If left unchecked, the male caique may kill its mate (Ireland, 1988; Lima, 1996). Tom Ireland was not able to rehabilitate his overly aggressive male caiques, but Ralph Lima claimed some success by pairing them up with new mates.
Once the female is receptive, copulation begins. Like all South American parrots, male caiques grip the perch with one foot and place the other on the female’s back. This is different from how old world parrots copulate in which the male stands with both feet on the female’s back (Smith, 1978). Male caiques, like most parrots do not have a penis or other organ for deposition of their sperm into the female’s cloaca. Rather, it is done by a sort of “kissing” of the claoca’s of the two birds. Caiques are not shy about copulation and the act can last for longer than a quarter of an hour. Some pairs make a very distinctive sound during copulation, and for me this is one of the earliest indications that egg laying will soon occur. The hen cannot store sperm, so for an egg to be fertile it must be laid within 48 hours of copulation (Reillo, 1998). This may explain why the male is so obsessed with mating and tries to copulate with the female at every opportunity until the all the eggs are laid. Only after the female is busy incubating the eggs and less inclined to leave the nest box does he relent.
The commencement of egg laying is indicated by several behaviors. One of the surest is that the hen chews on objects she normally avoids. Unfortunately for the owner, plaster walls and wall board are a favorite even though you may have supplied them with a mineral block made out the same gypsum. They will almost always chew on cuttlebone, so be sure every hen has available in its cage. The hen also begins to consume more water. Eggs require a lot of water. If you use a water bottle, you will notice an increase in consumption (Wissman, 1999). Eggs are laid over a period of time; there is usually a gap of about three or four days between eggs. The hen does all the incubation. Once the eggs are laid the male is much less aggressive toward the female, but takes great interest in the nest. The male often visits the box while the female is out eating. The female usually does not begin incubating in earnest until after at least two eggs are laid.
You need to monitor the health of the female once she is gravid, i.e., exhibits an enlarged abdomen due the egg. She may experience egg binding, or sometimes more serious maladies. On rare occasions, the ovum instead of making the proper descent of the oviduct develops in the abdomen. This happens when the infundibulum fails to catch the newly fertilized ovum and it falls into the abdomen. If the egg is not reabsorbed, this can lead to a life threatening infection called “egg-yolk peritonitis.” It results in a build up of fluid in the hen’s abdomen and makes her appear to be gravid. If the hen goes for more than a week in what appears to be an extreme gravid condition without laying an egg, she may be suffering from binding or peritonitis and must be watched closely. If she becomes wobbly on the perch or goes to the bottom of the cage, you need to get her to a veterinarian immediately.
G. Egg laying.
If one has multiple pairs, the same pair usually takes the lead in laying the first clutch of eggs every season (Ireland, 1988; Reillo, 1998). Their mating and egg laying activity then sets off a chain reaction of mating and egg laying by the other pairs. Once egg laying commences, the hen usually lays one every two to three days. The interval between eggs, however, can be as long as five days. The typical clutch size is three to four eggs. In some years, a hen may lay only one or two. Often they will lay five and the largest clutch size reported is seven eggs (Lima, 1996). The hen does all the incubation, but sitting usually does not begin in earnest until after the second or third egg is laid.
Statistically, fertile eggs tend to be larger and heavier than infertile ones (Reillo, 1998), but the scatter in the data renders this of little use to the average breeder. Eggs laid earlier in the season are more likely to be fertile than those laid later (Reillo, 1998). I have also noticed that a greater portion of the eggs produced by my oldest pair are infertile. This pair has been together for sixteen years, so parent age may also be a factor in fertility.
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Green-thighed caiques. An assistant allopreens as male treads on female. Photo taken by author at São Paulo Zoo in 2003. There were thirteen green-thighs in this cage. The cage was about 2 m wide, 3 m deep and extended about 3 m above an earthen floor.
H. Parent Incubation.
The female usually sits very tightly on the eggs and leaves the box only briefly to feed and defecate. The male spends some in the box with her, but during day light hours usually spends most of his time outside but near the box entrance. Toward the end of the incubation period the hen may bathe more frequently. It is speculated that this is how she controls the moisture in the box (Them, 1988). For this reason, it is important to always allow access to a shallow bowl of water. Smith (1972) suggests that if the female does not bathe very often and has a history of low hatch rate, you should add half cup of tepid water to the dry matrix in the box once a week. If there is an inch or more of bedding, there should not be any problem with the water being absorbed.
During the incubation period, the hen “talks” to her eggs. If you were unaware that your hen was sitting on eggs, the distinctive sounds of a sitting hen will give you another message. Dr. Gilbert Gottlieb (1997) has done some interesting studies with ducks and shown that this is important for the hatchling to be able to recognize its own species. Oddly, in his studies even the peeps made by other ducklings while still in the egg contribute to this capacity. In his experiments, he showed that when the parent duck incubated duck eggs or if a group of eggs are hatched in an incubator, the newly hatched ducklings were more attracted to a duck’s sound than a chicken’s sound. In contrast, if the ducklings were harmlessly muted while still in the egg several days before hatch, they were attracted to both about equally. Whether this is important for caiques is a bit of a question, since they do not have an ear opening for a week or more after they hatch. So whether “egg talking” is important for preconditioning the hatching egg to life after hatch or stimulates the hen’s mate to a more solicitous behavior remains a question.
One problem when the hen sits on her eggs as soon as they are laid is that the chicks hatch in the same order a few days apart. This is called asynchronistic hatching as opposed to when all the chicks hatch at one time, or synchronistic hatching such as seen for chickens and ducks. This is a major problem is you expect all the chicks to survive. When the chicks hatch asynchronisticly, the oldest chick is often the only one to survive. This is because the chicks that hatch later are not able to compete as effectively for food and attention (Smith, 1991). To avoid this problem you need to intervene and there are a number of ways to do this. If you have a large number of pairs laying eggs, you can shift the eggs around so that eggs laid on one day are all set beneath one hen. Another way is to remove the first two eggs as they are laid and replace them with artificial eggs. Then, after the third and usually last egg is laid, replace the artificial ones with the real eggs. This usually results in all three eggs, the typical clutch size, hatching at about the same time. The removed eggs should be stored at room temperature, i.e., about 75ºF. The hen sometimes does this herself and does not begin to sit tightly until after the third egg is laid. Then, when the chicks all hatch at the same time, they compete at the same level for the attention of the parents and stand a much better chance for survival. Still another approach, and the one I use, is to leave the eggs with the hen and allow the eggs to hatch in the same order they were laid. Then I pull the oldest chick for hand-feeding one or two days after each successive chick hatches. When this is done, the parents never have to feed more than two chicks at any one time. Since there is usually a three or four day lapse between the hatching of the eggs, the chicks receive the benefit the parents feeding for a short interval. It is much easier to hand-feed a chick that has been fed even a few days by the parents than a day-one hatchling. Using this method, I have suffered far fewer losses of chicks than any of the other methods I have tried.
People who breed parrots usually try to prevent outside disturbances of their aviary during the breeding, incubation and early parent rearing periods. This is less of a problem with domestically bred stock habituated to humans, but it was a problem for aviculturists in earlier years when only wild caught stock was available (Manning, 1991). Some pairs particularly in public aviaries are so inured to people now they go to nest even when there is a general hubbub of activity outside their cages. Most pairs in private hands are not so habituated, and the female feels compelled to pop out and see what is happening every time she hears a strange person or animal come near the cage. My pairs are not particularly bothered by disturbances as long as they know they are a part of the daily routine, even when I inspect the nest box. The disturbances that bother them most are unexpected visits by too many strange people and unknown animals such as cats and dogs. In general, if you avoid changing the daily routine, particularly their feeding schedule (Manning, 1991), during the breeding period the birds usually remain content and produce chicks year after year.