AndreaFahy
04-20-2007, 11:04 PM
Environment
Light - neuroendocrine systems control the annual development of the
reproductive system with sufficient precision to assure that young will be
produced when trophic (feeding/nutrition) resources are optimal.
Climate - High temperatures combined with high humidity increases physiological stress on birds, therefore often decreasing reproductive activity. Rainfall has been proven to trigger courtship behavior in male zebra finches.
Season - Heavily domesticated species are not so much affected by season. Other species have different breeding seasons that are still instintual.
Mate Presence - Separating a pair during the non-breeding season may not affect reproductive success in a subsequent season. A bonded pair under the right conditions will mate.
Mate Selection - Forced pairing may result in increased mate aggression.
Specific mate characteristics may affect mate acceptance and the strength of the pair bond. Some aggressive mates can inhibit reproduction by actually preventing the opposite sex from eating or even through direct physical abuse.
Mate Pair-bonding - Pair-bonding is the behavioral acceptance that exists
between a compatible hen and cock and is evident in all successful pairs.
Mate Vocalization - Male auditory signals stimulate female reproduction in
several species.
Social Interaction - Other breeding birds in the presence is a reproductive
stimulus in highly social and colony breeding species.
Human Interaction - Human interference can affect reproduction. Disturbances can disrupt endocrine control of the reproductive cycle or distrub the birds so that mating is not initiated or completed, incubation is interupted, eggs are damaged or chicks are cared for improperly.
Nests - Availability and acquisition of a proper nest site and nesting material may be a strong environmental stimulus for breeding.
Territory - In finches, males with a breeding territory had larger testes with a longer functional period than males that were photo-stimulated without a
breeding territory.
Enclosures - Some species are more inclined to breed in flights, others in
enclosures. An enclosure too large can inhibit reproduction as the pair may not feel they can adequately defend the territory.
Hand Raising - Hand raising neonates may result in imprinting on humans or a lack of early environmental learning, which may affect future reproductive success. Imprinting often appears stronger in males.
Nutrition - Low dietary calcium levels (0.056%-0.3%) have been shown to cause a complete cessation of egg laying in gallinaceous birds (domestic poultry, gamebirds). Decreased energy intake causes decreased LH levels followed by ovarian atresia. Low-sodium diets also result in cessation of egg laying. Zinc-rich diets decrease feed intake and may directly decrease egg laying by altering metabolism and endocrine functions. Over nutrition may precipitate infertility by either mechanically blocking the cloaca or reducing successful ovulation. Abdominal fat and lack of condition may contribute to oviduct inertia and egg laying problems.
Source: "Avian Medicine: Principles and Application"
by: Ritchie, Harrison & Harrison
Light - neuroendocrine systems control the annual development of the
reproductive system with sufficient precision to assure that young will be
produced when trophic (feeding/nutrition) resources are optimal.
Climate - High temperatures combined with high humidity increases physiological stress on birds, therefore often decreasing reproductive activity. Rainfall has been proven to trigger courtship behavior in male zebra finches.
Season - Heavily domesticated species are not so much affected by season. Other species have different breeding seasons that are still instintual.
Mate Presence - Separating a pair during the non-breeding season may not affect reproductive success in a subsequent season. A bonded pair under the right conditions will mate.
Mate Selection - Forced pairing may result in increased mate aggression.
Specific mate characteristics may affect mate acceptance and the strength of the pair bond. Some aggressive mates can inhibit reproduction by actually preventing the opposite sex from eating or even through direct physical abuse.
Mate Pair-bonding - Pair-bonding is the behavioral acceptance that exists
between a compatible hen and cock and is evident in all successful pairs.
Mate Vocalization - Male auditory signals stimulate female reproduction in
several species.
Social Interaction - Other breeding birds in the presence is a reproductive
stimulus in highly social and colony breeding species.
Human Interaction - Human interference can affect reproduction. Disturbances can disrupt endocrine control of the reproductive cycle or distrub the birds so that mating is not initiated or completed, incubation is interupted, eggs are damaged or chicks are cared for improperly.
Nests - Availability and acquisition of a proper nest site and nesting material may be a strong environmental stimulus for breeding.
Territory - In finches, males with a breeding territory had larger testes with a longer functional period than males that were photo-stimulated without a
breeding territory.
Enclosures - Some species are more inclined to breed in flights, others in
enclosures. An enclosure too large can inhibit reproduction as the pair may not feel they can adequately defend the territory.
Hand Raising - Hand raising neonates may result in imprinting on humans or a lack of early environmental learning, which may affect future reproductive success. Imprinting often appears stronger in males.
Nutrition - Low dietary calcium levels (0.056%-0.3%) have been shown to cause a complete cessation of egg laying in gallinaceous birds (domestic poultry, gamebirds). Decreased energy intake causes decreased LH levels followed by ovarian atresia. Low-sodium diets also result in cessation of egg laying. Zinc-rich diets decrease feed intake and may directly decrease egg laying by altering metabolism and endocrine functions. Over nutrition may precipitate infertility by either mechanically blocking the cloaca or reducing successful ovulation. Abdominal fat and lack of condition may contribute to oviduct inertia and egg laying problems.
Source: "Avian Medicine: Principles and Application"
by: Ritchie, Harrison & Harrison