Discussion to nesting

[marika.solo]

Reverse Mating in Birds: Scientific Explanation

While most bird matings occur in the "male-on-female" position, the reverse has been observed in dozens of species, including both White and Black Storks.

1. Social Bonding
Experts agree that for species with long-term pair bonds (like storks), mating serves functions beyond just reproduction. Many instances of reverse mounting occur when the female is no longer fertile (e.g., during incubation). It serves to:
- Pair Synchronisation: Strengthening trust and coordination between partners.
- Aggression Reduction: Helping partners habituate to physical closeness without conflict.

2. Signaling Quality and Dominance
Some studies suggest this behaviour is a form of intra-pair communication:
- Mutual Stimulation: It acts as a ritual that stimulates hormonal levels in both partners, which is crucial for successful chick rearing.
- Stability Testing: The female may "test" the male's willingness to submit and remain at the nest.

3. Anatomical Safety (Regarding the Eggs)
The Nest Cup: Birds create a hollow in the nest where eggs are protected from direct pressure.
- Weight Distribution: When the female mounts the male, her weight is transferred to the male’s body, not the eggs. Thanks to his sturdy skeletal structure and musculature, he absorbs the pressure without the eggs underneath being harmed.

4. Statistical Occurrence
While it may seem unusual, in certain species (e.g., Grebes, Cormorants, or Raptors), reverse mounting accounts for a significant percentage of all sexual interactions. In storks, this often happens during the "change of guard" at the nest, when excitement and pair-bonding displays are at their peak.

Summary of the Literature
Experts do not view this behavior as a "mistake" or "confusion" on the part of the birds, but rather as a sophisticated communication tool that helps the pair manage the stress of the breeding season and reinforce their bond.