Weight management in micro raptors
Nov 24, 2013 21:07:08 GMT -5
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Post by Falcon Boy on Nov 24, 2013 21:07:08 GMT -5
In this article I will discuss my view on weight management in the micro raptors. Please note that many of these ideas are not my own, but rather more of a conflagration of different people’s writings and a few helpful tips I’ve picked up from friends along the way. Everything below is my views on weight management for micro raptors, but a lot of it can be translated to larger species.
Everything I’ll discuss in this article is based on the following assumptions: the bird is kept indoors at a consistent temperature, you keep a log of your birds weight and what it eats and how it flies etc., you can control the day and night cycles, and you weigh in grams (weighing micro raptors in ounces is, in my view, completely unacceptable). In addition, I am of the opinion that you should NEVER UNDER ANY CIRCUMSTANCE FEED WASHED MEAT TO ANY RAPTOR.
Before we begin, I must add that weighing your bird more than once of day should be a requirement in micro raptor management. We weigh our micro birds at least three times a day: when we wake up, when we get home from work, and before we go to bed. It is not unusual for us to weigh our birds five times a day. Micro birds can lose weight quickly, and if they get too low in weight, they will suffer. It is the falconer’s duty to be diligent in their weight management.
Calculating Weight Loss
Calculating weight loss is incredibly simple, as it requires only basic division skills. In essence, what we are looking for is the average grams per hour that the bird loses. The amount of weight lost per hour will vary according to what the bird ate, how long it has been since it ate, the temperature, whether its light or dark, its level of physical activity, if it flew that day, how much it flew that day, and about a billion other confounding variables. However, by calculating weight loss in the form of average grams per hour lost we can predict where the bird’s weight will be at any given point in time. When you’re good, as you should be with a micro raptor, you should be able to have your bird within .1g of the weight you desire. Failure to comprehend weight management in micro raptors can lead to their death.
The formula to calculate weight loss is quite simple: divide the number of grams the bird lost since it was last weighed by the number of hours it’s been since it was last weighed. For instance, if a bird at 2pm weighs 136g, and at 8pm weighs 132g, than we would do the following: 4g/6hours = .67g/hour burned.
That said, when I calculate weight I look at three main factors: food source, level of physical activity, and number of hours of “daylight.”
The food source is important as different food sources have different nutritional values. For instance, quail might be processed faster than pigeon, but at an equivalent speed to mice. There is not really a way to know exactly how fast your bird will burn each type of food until you feed it and calculate the number of grams per hour lost. Of note here is the importance of feeding numerous food sources and including hearts, lungs, and liver from their prey animals in their diet. These organs have vitamins and minerals which I believe are essential to the bird’s health.
The level of physical activity is important because if a bird is flown very hard, its metabolism will likely be much faster than if it just sat on a perch all day. For example, on flying days the bird might burn more weight than non-flying days. These are all things which should be kept track of and anticipated.
The day and night cycle is important for similar reasons. Birds typically burn weight slightly slower at night than they do during the day because they’re sleeping.
So now that those are out of the way, here is what I typically do when I have a new bird. I weigh the bird as soon as it is equipped. I weigh the bird the same way every time, generally this means hooded, with jesses and a light weight swivel. I let the swivel hang to keep the results consistent. Some people try to hold the swivel so it doesn’t interfere with the weight, but I just don’t believe that is accurate enough for micro birds. Moving the swivel up and down in your hand can and will often change the weight. That’s why I just let it hang.
After the initial weight is recorded I usually weigh the bird 6-8 times a day for the first week or so. From all of this data, you should be able to extrapolate pretty accurate baselines of how much weight your bird loses during the day and during the night hours. Within 2-3 days you should have a pretty good grasp of the weight loss, accurate to say .2 or .3g, and within 5-6 you should be accurate to .1g. There are no excuses with micro birds’ weight management. If you mess up they can die. My advice is don’t mess up, and over feed if you’re afraid something might come up (i.e., might get home from work late that day). I’d rather delay hawking by a few hours than come home to a sick bird.
Weight is not just a number
This seems a difficult concept for people to grasp, and I have no idea why. There are a million things which can affect how a bird will fly, weight, temperature, time since it last ate, what it last ate, when it last cast, the field it’s being flown in, etc. Which should make this concept quite simple to understand.
Here is a hypothetical situation. Someone says their bird is right at weight, let’s say at 10am. However, at 7am the bird ate 20g of quail, meaning it was low in the morning. When they go to fly it, it just acts like a slightly fat bird, being picky and choosey with it’s flights. Since it was at weight, why did it not fly well? Because it ate 3 hours before. If you eat a late lunch, are you as hungry at your normal dinner time? Of course not! Why would birds be any different?
That said, you can sometimes have a bird at weight but give it a small snack to increase its energy before flying. But that is something more advanced and I don’t think it’s very useful for this discussion. The point is, weight is not just a number. A lot of things can affect a birds performance, you just need to figure out the right combination for your bird.
Flying weight vs hunting weight
A lot of birds will come to the lure or glove great at a certain weight, but not really hunt. Or they “just miss” every single time without fail when they should have caught the quarry. This is often the difference between flying weight and hunting weight. Many birds will fly slightly higher in weight than they will hunt. I’ve noticed this with American Kestrels in particular, but Harris’ hawks and Redtails do this too from what I’ve seen. Please do not confuse what I call “just miss syndrome” with inexperience. Chamber raised birds for instance have almost no experience footing prey and can sometimes take a while to get the hang of it. In cases where inexperience is the problem, it is not “just miss syndrome” and slight weight reduction probably isn’t the answer.
Number of feedings per day
I really recommend feeding micro raptors at least twice a day. The reason for this is two fold: 1) they have a fast metabolism, 2) I believe it helps prevent illness. The scariest thing with weight management in small raptors is fear of them getting too low. When this happens the bird’s system can shut down, so they won’t eat even though they’re starving to death. When I say they won’t eat, I mean they may show interest in food, but they throw it up a while later and don’t digest it. Obviously, this is terrible and the bird needs a vet asap.
So here is what I’ve been told. Obviously I have not tested it. But I’ve been told that if a bird gets low, but has eaten recently and has food going through it’s system, you can usually get it to recover without too much trouble. But if a bird gets low, and its system is empty (i.e. hasn’t eaten anything in quite a while, let’s say 24 hours), it is more likely to crash and have its system will shut down. As I said, I don’t know if this is true. I do know that the logic in it seems plausible to me. Accordingly, I always feed at least twice a day, even if it’s just a gram of food. Sometimes you can feed a bird and the sudden increase in food will increase their metabolism, which can help a bird make weight that might otherwise not have.
Food manipulation and casting material
I am of the opinion that casting material is 100% necessary for all raptors. It helps clean out their system and my birds have always seemed keener to hunt and eat if they put forth a good casting in the morning. With micro raptors I tend to use quail necks and heads (with feathers on them) as the casting materials unless they caught game that day (in which case they eat what they caught).
You can be strategic about what foods you feed. For instance, I know that my bird will burn pigeon at about the same rate as quail. However, I know that if I feed him the head and neck of a quail, i.e. primarily casting material, I can feed him about 85-90% his normal ration of pigeon, plus the addition head and neck of the quail. In total that means the bird might eat 40-50g of food, but he will still make weight the next day. Why? Because he processes the food faster because the casting material doesn’t really have much nutrients in it. But why would you want to do this? The logic is simple and twofold: 1) the bird gets casting material, which as I’ve stated, I believe is of the utmost importance to their health, and 2) the bird gets to eat more, which they think is a bigger reward for the desired behavior. So the bird gets a nice big crop of food and feels very “happy” but at the same time makes weight the next day and casts. There are other ways you can do this too, such as feeding a certain percentage of one type of food, and a certain percentage of another type of food, but I don’t really want to get into that.
Conclusion
I hope this primer has helped you understand a bit more about micro raptor weight management. It is time consuming and does take dedication. But once you figure it out it becomes second nature. Weighing the bird only takes a few minutes, and when you make it a habit to weigh the bird a few times a day it just becomes part of the normal falconry routine.
Everything I’ll discuss in this article is based on the following assumptions: the bird is kept indoors at a consistent temperature, you keep a log of your birds weight and what it eats and how it flies etc., you can control the day and night cycles, and you weigh in grams (weighing micro raptors in ounces is, in my view, completely unacceptable). In addition, I am of the opinion that you should NEVER UNDER ANY CIRCUMSTANCE FEED WASHED MEAT TO ANY RAPTOR.
Before we begin, I must add that weighing your bird more than once of day should be a requirement in micro raptor management. We weigh our micro birds at least three times a day: when we wake up, when we get home from work, and before we go to bed. It is not unusual for us to weigh our birds five times a day. Micro birds can lose weight quickly, and if they get too low in weight, they will suffer. It is the falconer’s duty to be diligent in their weight management.
Calculating Weight Loss
Calculating weight loss is incredibly simple, as it requires only basic division skills. In essence, what we are looking for is the average grams per hour that the bird loses. The amount of weight lost per hour will vary according to what the bird ate, how long it has been since it ate, the temperature, whether its light or dark, its level of physical activity, if it flew that day, how much it flew that day, and about a billion other confounding variables. However, by calculating weight loss in the form of average grams per hour lost we can predict where the bird’s weight will be at any given point in time. When you’re good, as you should be with a micro raptor, you should be able to have your bird within .1g of the weight you desire. Failure to comprehend weight management in micro raptors can lead to their death.
The formula to calculate weight loss is quite simple: divide the number of grams the bird lost since it was last weighed by the number of hours it’s been since it was last weighed. For instance, if a bird at 2pm weighs 136g, and at 8pm weighs 132g, than we would do the following: 4g/6hours = .67g/hour burned.
That said, when I calculate weight I look at three main factors: food source, level of physical activity, and number of hours of “daylight.”
The food source is important as different food sources have different nutritional values. For instance, quail might be processed faster than pigeon, but at an equivalent speed to mice. There is not really a way to know exactly how fast your bird will burn each type of food until you feed it and calculate the number of grams per hour lost. Of note here is the importance of feeding numerous food sources and including hearts, lungs, and liver from their prey animals in their diet. These organs have vitamins and minerals which I believe are essential to the bird’s health.
The level of physical activity is important because if a bird is flown very hard, its metabolism will likely be much faster than if it just sat on a perch all day. For example, on flying days the bird might burn more weight than non-flying days. These are all things which should be kept track of and anticipated.
The day and night cycle is important for similar reasons. Birds typically burn weight slightly slower at night than they do during the day because they’re sleeping.
So now that those are out of the way, here is what I typically do when I have a new bird. I weigh the bird as soon as it is equipped. I weigh the bird the same way every time, generally this means hooded, with jesses and a light weight swivel. I let the swivel hang to keep the results consistent. Some people try to hold the swivel so it doesn’t interfere with the weight, but I just don’t believe that is accurate enough for micro birds. Moving the swivel up and down in your hand can and will often change the weight. That’s why I just let it hang.
After the initial weight is recorded I usually weigh the bird 6-8 times a day for the first week or so. From all of this data, you should be able to extrapolate pretty accurate baselines of how much weight your bird loses during the day and during the night hours. Within 2-3 days you should have a pretty good grasp of the weight loss, accurate to say .2 or .3g, and within 5-6 you should be accurate to .1g. There are no excuses with micro birds’ weight management. If you mess up they can die. My advice is don’t mess up, and over feed if you’re afraid something might come up (i.e., might get home from work late that day). I’d rather delay hawking by a few hours than come home to a sick bird.
Weight is not just a number
This seems a difficult concept for people to grasp, and I have no idea why. There are a million things which can affect how a bird will fly, weight, temperature, time since it last ate, what it last ate, when it last cast, the field it’s being flown in, etc. Which should make this concept quite simple to understand.
Here is a hypothetical situation. Someone says their bird is right at weight, let’s say at 10am. However, at 7am the bird ate 20g of quail, meaning it was low in the morning. When they go to fly it, it just acts like a slightly fat bird, being picky and choosey with it’s flights. Since it was at weight, why did it not fly well? Because it ate 3 hours before. If you eat a late lunch, are you as hungry at your normal dinner time? Of course not! Why would birds be any different?
That said, you can sometimes have a bird at weight but give it a small snack to increase its energy before flying. But that is something more advanced and I don’t think it’s very useful for this discussion. The point is, weight is not just a number. A lot of things can affect a birds performance, you just need to figure out the right combination for your bird.
Flying weight vs hunting weight
A lot of birds will come to the lure or glove great at a certain weight, but not really hunt. Or they “just miss” every single time without fail when they should have caught the quarry. This is often the difference between flying weight and hunting weight. Many birds will fly slightly higher in weight than they will hunt. I’ve noticed this with American Kestrels in particular, but Harris’ hawks and Redtails do this too from what I’ve seen. Please do not confuse what I call “just miss syndrome” with inexperience. Chamber raised birds for instance have almost no experience footing prey and can sometimes take a while to get the hang of it. In cases where inexperience is the problem, it is not “just miss syndrome” and slight weight reduction probably isn’t the answer.
Number of feedings per day
I really recommend feeding micro raptors at least twice a day. The reason for this is two fold: 1) they have a fast metabolism, 2) I believe it helps prevent illness. The scariest thing with weight management in small raptors is fear of them getting too low. When this happens the bird’s system can shut down, so they won’t eat even though they’re starving to death. When I say they won’t eat, I mean they may show interest in food, but they throw it up a while later and don’t digest it. Obviously, this is terrible and the bird needs a vet asap.
So here is what I’ve been told. Obviously I have not tested it. But I’ve been told that if a bird gets low, but has eaten recently and has food going through it’s system, you can usually get it to recover without too much trouble. But if a bird gets low, and its system is empty (i.e. hasn’t eaten anything in quite a while, let’s say 24 hours), it is more likely to crash and have its system will shut down. As I said, I don’t know if this is true. I do know that the logic in it seems plausible to me. Accordingly, I always feed at least twice a day, even if it’s just a gram of food. Sometimes you can feed a bird and the sudden increase in food will increase their metabolism, which can help a bird make weight that might otherwise not have.
Food manipulation and casting material
I am of the opinion that casting material is 100% necessary for all raptors. It helps clean out their system and my birds have always seemed keener to hunt and eat if they put forth a good casting in the morning. With micro raptors I tend to use quail necks and heads (with feathers on them) as the casting materials unless they caught game that day (in which case they eat what they caught).
You can be strategic about what foods you feed. For instance, I know that my bird will burn pigeon at about the same rate as quail. However, I know that if I feed him the head and neck of a quail, i.e. primarily casting material, I can feed him about 85-90% his normal ration of pigeon, plus the addition head and neck of the quail. In total that means the bird might eat 40-50g of food, but he will still make weight the next day. Why? Because he processes the food faster because the casting material doesn’t really have much nutrients in it. But why would you want to do this? The logic is simple and twofold: 1) the bird gets casting material, which as I’ve stated, I believe is of the utmost importance to their health, and 2) the bird gets to eat more, which they think is a bigger reward for the desired behavior. So the bird gets a nice big crop of food and feels very “happy” but at the same time makes weight the next day and casts. There are other ways you can do this too, such as feeding a certain percentage of one type of food, and a certain percentage of another type of food, but I don’t really want to get into that.
Conclusion
I hope this primer has helped you understand a bit more about micro raptor weight management. It is time consuming and does take dedication. But once you figure it out it becomes second nature. Weighing the bird only takes a few minutes, and when you make it a habit to weigh the bird a few times a day it just becomes part of the normal falconry routine.
