Showing posts with label behavior. Show all posts
Showing posts with label behavior. Show all posts

Saturday, November 13, 2010

Puerto Rican parrot twilight behavior, sleeping clumped in a bunch.

This is the only photo of this behavior ever taken, you can see a parrot ready to fly away at the bottom
As the leader of the captive propagation program of the Puerto Rican parrot I spend time, probably than anyone on its right mind should, observing parrot behavior. I also read the notes of previous aviculturists about the parrot’s behavior in captivity to look for context for my observations. But there is a gap in the information about this parrot’s behavior, there’s an absolute absence of writings on what the parrots do after dark. In fact most people seem to assume that as soon as night falls the parrots go to sleep and that’s that. To say the truth this inference is largely true, however in the period of twilight before complete darkness the parrots do things that have been missed, as far as I can tell, by other observers.


The reason for missing these behaviors is very simple, after the daily work shift ends the personnel goes to their houses, to do errands, to take a nap, to eat, and hanging around the parrot cages is the last thing in (including me) anyone’s mind. But one day I noted that the period of twilight was marked by an inordinate amount of calls coming from a relatively small area in the cage, the calls denoted intense socialization at a time that I had always assumed the birds were setting down to sleep. This piqued my curiosity and I decided to see what was happening.

What I found is that sometimes, instead of sitting on the many perches on the cage, the parrots will cluster together to sleep in the wire forming a mass that resembles a grape bunch. I have never read this reported, and it doesn’t seem like they sleep in this way in the wild. The birds arrange themselves in a very tight bunch, literally side by side in a degree of intimate contact that I would have thought inconceivable between adult parrots that are not pair bonded. The forming of the bunch is accompanied by much squawking and I suspect this is caused by birds jostling each other for position on the bunch. I have never set out to watch the formation of the bunch since this would probably disrupt its formation but I have on rare occasions witnessed its dissolution. Also most of our flight cages have, by design but this is a matter for another post, odd asymmetrical shapes that limit line-of –sight viewing.  What I found most interesting about this clumping behavior is that the PR parrots, which can be quite picky with who they associate during the day, seem to lose their selectivity as night falls and join together in relative amicability and closeness that they don't show during the day.

I suspect the birds clump as a form of protection from predators. I make this inference because of what happens when the clump is disturbed. When the birds are startled the clump explodes like a grenade with birds flying in all directions. I have just a single photo of this clumping, it was taken when I had to feed the flock very early before dawn because we were doing some special work with the wild birds and I wanted the captive birds to be all fed by first light in the morning. In the photo you can see only part of the clump as a number of the birds had flown away the moment they detected movement near the cage. Nevertheless the photo shows the way the birds arrange themselves on the wire. Previously I always thought that only mated pairs slept this way.

It is unclear what triggers this behavior as some birds are quite content to sleep in perches.  For the moment being this behavior remains a curiosity observed from time to time.

Sunday, October 24, 2010

The female red jewel fish Hemichromis lifalili and her fry




The eggs of the female Hemichromis lifalili about which I wrote in an earlier post hatched during the weekend. The fry are now at the bottom of the cavity where spawning occurred. The fry are full of vibrant activity as they all move their tiny tails incessantly. At this stage of their development they are called fry because they hardly resemble a proper fish. In the image you can see the mass fry but only the yolk sacs can be seen clearly. The yolk sacks are attached to the belly of the fry. The fry are little more than a line of muscle tissue a few millimeters long. Because the fry are vigorously shaking their tiny bodies and are transparent they cannot be seen well in the picture which shows the massed fry. But we can distinguish some black dots above the yolk sacs. These dots give rise to the eyes and nervous system of fishes.
The female defends her fry with impressive ferocity, in the images we can see that it has a bite on the area over the mouth. I do not know which of the fish in the tank bit her but I suspect it was the male with whom she spawned . To my surprise the female was aggressive when the male approached the spawning cave and stopped him from to entering it. She blocked him from entering where the the fry were by arching her body and lifting the scales covering the gills. The male spent most of his time on the other side of the tank with the other fish, his level of aggressiveness was mild compared with that of the female.
The previous spawning that occurred in the tank was the product of the male of this spawning but with a different female. Apparently the male lost interest in that spawning the moment the fry were born and left the female alone to defending their offspring. The female of the previous spawning took the fry from the trunk and hid it in a depression in the material at the bottom of the tank, but she could not defend the fry from the other fish and lost them all.
In a few days the female of this photo also have to move their young to the bottom of the tank to allow them to forage for food. It remains to be seen whether the male will help her defend them. From what I could see the males showed a somewhat ambiguous behavior, he seemed to behave aggressively but at the same time he was obviously eyeing the other females, the latter development does not augur well for the survival of the fry.

A red Jewel fish (Hemichromis lifalili) female tending her eggs


In this image we can see a female lifalili tending her recently spawned eggs. The female is using her pectoral fins to create currents of water over the eggs so that they receive the oxygen they need to live. The female also mouths the eggs. I have read that the female removes from the spawn those eggs that become infected by fungus. This spawn is in an immaculate condition so it seems that the female is successfully managing to control the attack of the fungus on her eggs . This is the second spawning of my lifalili. These fish have been surprisingly precocious, they began to spawn when just a little bit over about two inches in lenght, about four weeks after they are acquired. It is said that adults can reach six inches long but the most of those I've seen locally are no more than four. When these fish are in the process of spawning they become especially aggressive toward other fish. To achieve this image I had to plan carefully how to provide them with a suitable spawning site that would also allow for ease of photographing. The lifalili seem to prefer spawning in enclosed areas. For this reason it is common for aquarists to provide them with terracotta pots usually placed on their side. The problem is that this type of arrangement, in a tank like mine, makes it difficult to photograph the fish caring for the eggs and fry. I put in the tank two pieces of ceramic that resemble a mass of roots and which have at their top tubular cavities that open toward the surface.. To reduce the potential of a spawning in a hidden or inaccessible elsewhere in the tank I do not use any other object that has a cavity suitable for spawning. Since the opening of the cavity is facing the surface it is relatively easy to photograph the female taking care of the eggs.

Tuesday, October 19, 2010

Zoogoneticus tequila, English version


They come from central Mexico, the females are assertive, powerful and the males desire and fear them. The males are handsome, aggressive but cannot avoid being controlled by the females which henpeck them mercilessly. I'm not referring in these lines to the plot Mexico's latest soap, but the behavior of the viviparous Mexican fish Zoogoneticus tequila.

The Zoogoneticus tequila is known in English as the "Crescent Goodeid" due to the coloration of the tail fin of the male or the "Tequila splitfin" in recognition of the anatomy of the anal fin of fish in the Goodeidae family. I don't know if it has been awarded a common name in Spanish as it is not available locally in the commercial aquarium trade but in this article it will be called the Tequila. The Tequila nickname refers to a volcano in the vicinity of its natural habitat. Fish of the Goodeidae family are distinguished by a number of fascinating biological and anatomical adaptations that separate them from other livebearers, these make them an interesting subject for the aquarist. Their behavior is also of interest because unlike other viviparous fished Zoogoneticus interacts with other fish in the same way that Mike Tyson interacted with Evander Hollyfield's ear in that unforgetable fight.
We will start by detailing the reproductive adaptations of this species. The male fish of the family Goodeidae lack a gonopodium, this immediately distinguishes Zoogoneticus from other viviparous fish common in the market such as guppies, swordtails and mollies. Because they have no specialized structure such as the gonopodium, males use the first few anal fin spines to transfer sperm to the female. The females do not store sperm so they have to be fertilized every time they produce a litter, in this respect they are unlike the Poeciliae such as guppies and mollies. The young develop inside the female and produce a structure called trophotaenia which comes out of their bellies and allow them to absorb nutrients from the mother's body. The females produce relatively few offspring compared with other livebearers, 10 to 15, but the young are much larger than usual in viviparous fish. The attitude of adults towards the young is similar the way Herod treated his own children. Adults actively hunt the young, they should be separated from them so they can survive. It is reported that the female gives birth roughly every two months.

Some species of the genus Zoogoneticus seem to have very restricted geographic distributions. Tequila has not been collected in the wild since 1990 and it is suspected it might have become extinct in the wild. Tequila was recognized as a new species in 1998 even though specimens had been collected since 1955. The species Tequila is related very closely with Zoogoneticus quitzeoensis described in 1898 and Zoo. purhepechus a new species described in 2008. Its origin lie in the state of Jalisco, in the river Teuchitlan.

Males are grayish, some scales of the sides of the body show a pink iridicensce. The females are generally gray but the ones I have show a fairly dark color probably because the level of illumination in their aquarium is low. My fish are still young so it is likely they will continue to change color as they mature.

I keep the fish in a tank 30 gallon long. The water in the tank has a pH of 7. The tank has no conventional ornaments. The bottom is covered with teak leaf litter, a soft mud that has resulted from the decomposition of the leaves and algae that has covered the remains of the leaves. Laying just below the water surface is a mass of plants, mainly Hygrophyla difformis. The temperature of the tank varies between 70F and 80F. I change about 80% of the tank water every two weeks.

The fish are fed three times a day, in the morning when I go to work, noon and in the evening just before sunset. If anything can be said of these fish is they eat everything I offer with a breathtaking lack of discriminating criteria. The cheapest flake food is eaten with the same zeal as the mosquito larvae,"bloodworms" and food pellets. I try to vary the diet a bit every day and while some days I give them bits of minced shrimp in others I give pellets. Different sources recommended that these fish should be fed with a vegetable-based food. But as the tank has a good growth of algae, I have not bothered to give any special vegetable based food.

In the beginning there were five Tequila in the tank, three females and two males. But the two largest females harassed the younger in a manner so barbarous I suspect it was killed or that it may have jumped from the tank as it disappeared a few days after they arrived at my home. This is illustrative of the character of this species. They are aggressive fish, truculent and lacking in subtlety. In short they have an horror of a personality. In this they are the veritable antithesis of the ideal fish we want in a community tank.

Tequila breeders recommended keeping this species in a species only aquarium. During a normal day the largest male harrases several times the smaller one. Males approach females with caution since unreceptive females can bite. Not a day has passed without seeing that a Tequila has lost a scale here or there or has a bite in one fin.

What role can play in our aquarium a fish with so abhorrent a personality?. It turns out that the inclination for discord and contention of this fish makes it perfect for aquariums with small cichlids of like personality. But its role is not simply to share the aquarium, the Tequila with their challenging personality can provide a distraction for the cichlids. By diverting the attention of the cichlids they can ameliorate in a small degree intraspecific aggression and when the reproduction of the cichlids occurs, the Tequila become a catalyst for the protective instincts of the cichlids toward their young.

My Tequila share a tank with five jewelfish juveniles, Hemichromis lifalili, a jewelfish from Congo or Zaire. The lifalili are famous for two reasons, one is that when breeding they develop one of the most spectacularly colorful nuptial dress of any freshwater fish. The other is their unfortunate tendency to murder, in a violent and bloody way, all the other fish when they have young to protect.

Even when they are young and small the lifalili are far from being like Mother Teresa and they spend a lot of time chasing and attacking each other. Sometimes they harass the Tequila in an absent minded sort of tokenish way, they reserve their worst venom for their own kind. So far as I can tell, I have not noticed that any lifalili has caused any apreciable harm to the Tequila, to the contrary, subdominant lifalili often spend much time hiding in the vegetation along with the long suffering Tequila males.

You should realize that in spite of what I recommend above, you can't drop the Tequila in a tank with cichlids and expect everything to be peaches and cream. Nothing can be further from the truth! There is no faster way to kill a Tequila that throwing it in a aquariun where some territorial cichlids are tending their fry. The Tequila should be housed with the cichlids when the cichlids are still young and in a aquarium large enough for them to escape the aggression of cichlids. But that is another theme and in the future I will dedicate an article to commenting it.

The Tequila are very alert of my presence near the tank and watch me intently when I sit down to look at them. They are less shy than the cichlids and are not intimidated when I approach with a camera. Every day I spend some time observing them and the fish have learned that when I arrive in the afternoon there will be a special treat. So when I sit next to the aquarium just before night fall they react with great excitement. They are so bold that I've seen the whisk away a piece of shrimp from a cichlid with such speed that the cichlid is left wondering what happened.

The Tequila eventually will be moved to their own tank as the adults lifalili reach a size of about six inches and even before reaching this size they become a mortal danger to the other fish when they have a school of young to protect.

As you have seen the fish Tequila are not for everyone. But they have a certain charm, in an horribly obnoxious way, that transcends the absence of bright colors and peaceful behavior