Figured Id re-post this from last year: Decided to write something about how birds react to cold weather: Surviving the cold temperatures we are having can be difficult for birds. Most birds maintain a much higher body temperature than we do; temperatures generally range from 100 F to 105 F, depending on the species. The central advantage of such a high body temperature is the increased speed of nerve transmission and muscle contraction. Nerve impulses from the brain can travel much faster than those of animals with lower body temperatures. Birds can react much faster than we could ever hope to. There is a cost associated with maintaining such a high body temperature; birds will need to fuel this metabolic furnace and when heat stressed they risk rapid overheating. Cold weather creates its own special challenges for birds, especially small ones. Heat loss follows a simple rule. The more surface area you have to volume, the more heat you will radiate. Imagine a beach ball sitting next to a golf ball. A beach ball has less surface area relative to the amount of volume inside the ball. It will radiate internal heat at a much slower rate. The golf ball has more surface area relative to the amount of volume within the ball and will lose heat at a much faster rate. Birds that live in colder climates tend to be larger due to this phenomenon. When the temperature drops, smaller birds will have a harder time retaining heat but can react in different ways to compensate. They can huddle together in common roosting sites, make physical adjustments to their feathers, fluffing them up to trap air, or increase metabolism by shivering. Mammals have the advantage of being able to generate heat without shivering; they can metabolize brown adipose tissue (brown fat) to release heat. When small mammals are cold stressed they simply use their brown fat reserves to generate heat, birds do not have brown fat and are unable to do this. Because of their smaller size and increased rate of heat loss, smaller song birds have a metabolic rate that ranges from approximately 35 to 65 times higher than mammals and other birds. The metabolic rate for small birds is one of the highest relative to body size. All birds have an optimal temperature range that is physiologically neutral for them. At this range they will have no need to use extra energy to either cool or heat themselves. When the temperature drops to the lower critical temperature LCT, the bird will have to shiver or increase its metabolism by increasing oxygen consumption. At the upper critical temperature UCT, the bird will need to lose excess heat through evaporative cooling/water loss. Take a look at the image provided and notice the thermoneutral zone where birds are neither heat stressed nor cold stressed. This range differs depending on the bird species and time of year. During this extremely low cold snap, birds in our area will be well below the LCT and stressed to stay warm. Feeding rates will increase dramatically, and birds will use many of the strategies mentioned above to make it through the cold snap.
Posted on: Wed, 07 Jan 2015 00:31:03 +0000
Trending Topics
Recently Viewed Topics
© 2015