Nesting boxes. Thinking Out of the Box

The British aviculturist E.J. Boosey published a book titled Parrots, Cockatoos and Macaws in 1956. This early avicultural work describes the breeding of several species. Information such as diet and nest are discussed. For every entry referring to a nesting box (pages 42, 45, 119-20, 129), the reference is for a standard grandfather clock type—a square box that is deeper than it is wide or long. The general rule, which I still follow for many species, is to measure the body from the tip of the head to the base of the tail for the nest box size. This measurement is used for the box length and width and twice or three times this dimension for depth. This rule is easily followed and has worked for many years. However, starting in the late 1980s I began questioning the use of the standard nest. Field work conducted over the following years revealed several key points:

  1. Parrots prefer the tightest fitting, darkest nest possible. This often results in their chick being unable to fledge and becoming entombed in the nest cavity. I will never forget seeing the chick of a pair of Green-winged Macaw Ara chloropterus in a village north of Manaus in Amazonian Brazil. According to the caboclos, they could see the nest across the river from their basic thatched home and intervened when it seemed the chick was doomed; the parents fed their single chick for almost one year and as the chick could not emerge through the entrance– a crack in the tree created by a fallen branch– the caboclos freed the young, but its feather condition was so deteriorated that the chick could not fly. It was a house pet and was visited by the parents when it climbed a tall tree adjacent to the house. I have also seen chicks frantically trying to escape the cavity in which they were born, with the parents calling them in an adjacent tree. In most cases had someone not intervened the young would have perished.
  2. Parrots species fall into one of two categories according to their nesting requirements: nest type generalists, meaning that they will accept any cavity available as long as it is dry, dark and often deep, and nest type specialists, which seem to utilize a specific type of nest. No genera falls strictly into one or the other category. As an example, Blue-fronted Amazons Amazona aestiva will utilize terrestrial or arboreal termitaria in northern and central Brazil, openings in cliff faces in parts of Bolivia and Brazil and Prosopis trees in Argentina. The Red-tailed Amazon Amazona brasiliensis will nest in tree cavities but also in arboreal epiphytes. I will never forget being told by the late Nelson Kawall that he had received nestling Red-tailed Amazons from a nest inside a clump of bromeliads. I laughed. At the time I was too focused on the concept that parrots only nested in tree cavities or termites’ nests. That report of nesting in a bromeliad, once confirmed, started my evolutionary thinking.

At the other extreme are the specialists. Brotogeris prefer arboreal termitarium. If these are unavailable in an area where they have become feral (as in Florida), they accept the next possibility: the rotting base of fronds of Canary Island Palms. I have found countless nests in Florida and not once have I found the White-winged Brotogeris versicolurus or Canary-winged Parakeets Brotogeris chiriri nesting in a cavity, even when available within sight of a roosting flock.

  1. Pairs will forego nesting if only a very large cavity is available, as this heightens the concern of a predator entering and devouring the incubating hen, eggs or chicks and thus making the expenditure of tremendous energy to reproduce wasteful. As an example I can cite an example from Miami Beach, Florida, where there is a large flock of feral Severe Macaws Ara severus. These birds visit my yard daily and came in flocks daily when the Melia tree had seeds; the tree was a casualty of Hurricane Wilma, which impacted with fierce winds in October 2005. After Hurricane Wilma passed, most of the dead Roystonea palms the flock used for nesting become unavailable; they cracked, making the fissure too large to contain a nest, or more often were blown over. As the breeding season approached, I could see bitter fights developing between pairs for the scant available cavities. I therefore hung excess nesting boxes that were laying around in Australian pines by a golf course near the house. Interestingly, the tiniest boxes that had been used by conures were usurped first; the small amazon boxes came second. The two large macaw nests I placed in the pines were inspected but never used. They were eventually taken over by possums and ultimately decomposed. The small boxes all fledged at least one young; the large boxes engendered an aggressive predator.
  2. Some nest types have better husbandry application than others. The best example that I can site is the “T”- or “Y” shaped cockatoo nests, which have two entrances and a division down the middle. This type of nest prevents an aggressive male from entombing the hen inside until she starves. It also makes killing her inside the nest more onerous. The double entrance permits the female to flee from a male intent on harming her. If the male’s wings are clipped, the hen has a significantly better chance of escaping unharmed than if a standard grandfather type nest was used. This style of nest can also be employed for other aggressive parrots, including Cuban Amazona leucocephala and Hispaniolan Amazons Amazona ventralis and the Australian Blue-bonnets (Northiella species).

The size of the this double entranced nest should be adapted for the size of the species for which it is offered.

  1. Some species are difficult to breed because they require a specialty nest—a box that breaks the standard concept in aviculture of the grandfather type box standing up or laying on its side, the latter most often used for macaws. I write this with the green conures of the genus Psittacara, a notoriously difficult group to induce to nest, in mind. Between 1988 and 1991, the USA imported at least 37,750 Mitred Conures Psittacara mitratus from Argentina according to the CITES (Convention on International Trade in Endangered Species) trade data that I reviewed; I looked at only large shipments; the actual figure of total imports would be significantly greater if small shipments are also tabulated. Even if only a percentage of these birds reached breeders, then in theory US aviculturists should be producing large numbers yearly. In fact, only a couple of handfuls of young are bred yearly. This species along with Wagler’s Psittacara wagleri, White-eyed Psittacara leucophthalmus and Red-masked Conures Psittacara erithrogenys have not proved willing breeders, though they are very successful in the wild and with the exception of the Wagler’s Conyre have a flourishing and growing feral population in Florida. Most pairs in captivity wait years to commence breeding. I often state that they finally accept the traditional nest because they have grown tired of waiting for a nest that they find suitable to be provided. For this group I have designed a ”C”-shaped nest; the nest is attached to the cage so that the actual nesting chamber sits above the front top of the cage and in a manner like a C that has fallen forward. This style of nest seems far more willingly accepted than the standard conure box (a vertical rectangle) typically offered. This same nest can be provided to other fickle breeders in two other positions: either vertically or flipped over horizontally to resemble a “U”. I find that some of the Eupsittula conures that nest in termitarium will take to it willingly when placed in the latter fashion. Some African Poicephalus, for example, like the nest in a vertical position.
  2. The use of an unconventional nests is necessary when a pair demonstrates that it dislikes the nest being offered. The best example that I can cite is a pair of Scarlet Macaws Ara macao in my collection. This pair never entered their nest, laying eggs from the perch. After two clutches of broken eggs and all attempts to entice them to enter a nest failed, I started to watch their behavior. This showed that the hen spent a lot of time on the enclosure floor, near the front. I then provided them with a chicken nest in that precise spot. Within a week the hen was inside. They now nest in that most usual nest that sits on their cage floor.
  3. Finally some species prone to egg breakage may respond very well to a specially adapted nest—the so-called B nest. The intention is to try and exclude the male, who is often the one responsible for egg-breaking, and to make the nesting chamber so dark that that the male is thwarted from easily visualizing and ultimately breaking the eggs. The narrow passageway to enter the nesting cavity and very dark interior often achieves this. This nest has been used for Blue-headed Macaw Primolius couloni, Hawk-headed Parrots Deroptyus accipitrinus and Black-headed Caiques Pionites melanocephalus pairs that had a history of breaking eggs.

The nests described above are only a sampling of what can be used or what should be kept in mind when developing yet another nest style. The key to success are to study the wild habits of the species which you are trying to breed, to then observe the behavior of the birds in your aviary, to accept no barrier in design, and to share the design that has led to the success so that others can also be successful. Only by doing this will aviculture be able to rewrite the standards put on paper by E.J. Boosey nearly six decades ago.