I've given up trying to write a full response, I can't get it short enough to post, so I'm just going to give some individual answers to your points from a couple of your posts, which is still very long :-(
Exactly, and that is the value of scientific publications as they allow scientists to share their first hand experiences with others, so we can all expand our personal, but very limited, first hand experience.
Avian scientists are the ones that spend thousands of hours in the field studying bird behaviour, they are the ones that record what birds are doing in a structured and objective way so the behaviour can be analysed. They are the ones that are sharing their data and experiences with thousands of other scientists so they can identify general patterns of behaviour as well as the variation in individual behaviour.
No avian scientist expects to exactly predict how an individual bird will behave in any particular set of circumstances but they will have a pool of knowledge from their own studies and the studies of others to draw upon when giving general advice.
For an individual issues, local knowledge becomes crucial. A local birder can bring a depth of knowledge about "their" local birds that the scientist can't hope to replicate in any reasonable time. Coupling this local knowledge along with the broader and more specialist knowledge of an avian scientist is the most effective route to answer or solve a specific bird conservation question/problem.
No need to overthink, in fact no need to spend much time thinking about it at all, you just need have some familiarity with the scientific literature on bird behaviour and be aware of how birds have reacted to similar interventions in the past.
Scientists don't share truths,. They seek the truth, and hope to find part of, what might be, a "possible" truth, which they then share as evidence supported scientific opinion.
How close a study provides an insight into the truth is judged by other scientists who scrutinise the quality of the data collection, the appropriateness of the data analysis and how plausible the interpretation of the analysis is. I can understand you challenging how well individual scientists adhere to the scientific process, and the process isn't perfect, but it’s still the process that should encourage confidence in scientific opinion, not challenge it.
While not all studies are of the same quality, and you are correct to not automatically believe the conclusions. But, the idea that scientists are sharing truths as they see them, or that they engineer studies to prove a theory, is just wrong. I'm not say it doesn't happen, but the entire scientific approach is designed to prevent it.
Starting with an easy one, If you have scientific theory you want accepted, you don't design a study to prove it correct, you design multiple studies to try and prove it wrong. You test the theory to destruction, only if it survives these tests will it be accepted by other scientists.
When a scientists "discovers" some new aspect of bird behaviour they will design a study to test if it really is new behaviour and not just some random event, they will also search the literature to check it really is new.
An early step is then to develop a study design. This lays out the data collection methods, and includes the measures being taken to ensure the data collection is objective and unbiased, and how you are ensuring that you are measuring what you think you are measuring. The deign will always include discussion with other scientists, and often (but not often enough) a statistician. The study design is always published and open to scrutiny.
The study design is a key stage, as your entire study relies on getting this right, and not all studies do. We were once asked to analyse data collected from a £600, 000 (yes really, 600,000) monitoring programme which had so many flaws in the study design that we had to turn down what would have been a lucrative contract.
The second stage is the analysis, and although there are multiple ways of analysing the same data, and there is a real possibility of getting this very wrong, again this is published, and increasingly the original raw data from studies are downloadable. This allows other scientists/statisticians to check the analysis and try alternative approaches. But the numbers you get are the numbers you get and those are the numbers published.
The third stage is the interpretation and conclusions, This is the opinion bit, this where the scientists explains, using the data and the data analysis in the paper as evidence, how their work contributes to our understanding of the world, how it contributes to getting us a bit closer to the truth. his part also points out any flaws in the study, highlights any areas of the conclusions that should be viewed with particular caution, and where identifies the need for any further work.
This third part is is the only part where the scientists expresses their "truths" about the study, and its always done in a cautious and tentative manner. Scientist don't think in terms of truths only in terms of what is most likely, given the evidence.
Its also the main area of scientific disagreement. The data is the data, and done well, this part is objective. The analysis is the analysis, and done well, its objective. But the interpretation of the analysis relies on professional judgement. Some scientists don't even read this part, and just look at the data and the data analysis parts
You are correct to be sceptical, but not as dismissive as you appear to be, about scientific opinion, as it's far from perfect.
However, given this opinion is usually based on evidence through published work, given that the entire structure of scientific study is to allow scientific opinion to be checked and tested by other scientists, and that science and the scientific method is rooted in ensuring an objective and unbiased approach, I would argue that scientific comment and advice is still likely to be the most reliable we have.
Scientific opinion shouldn't be blindly accepted, of course, but with a little effort you can usually find out enough about the science behind the opinion to assess its validity. This is particularly useful when scientific opinions are presented by the media, government or pressure groups, as I think, I have never found a scientific finding accurately reported. We used to do this as a class exercise, find the scientific paper behind a headline and see how close the newspaper (or government) report matched what the scientific paper had actually said
Why?
Avian scientists are totally immersed in their work, spend thousands of hours personally studying birds, spend thousands of hours reading papers from other scientists who spend thousands of hours personally studying birds, and spend thousands of hours working with conservation managers, zoos, game parks, developers etc working together to solve real world animal; protection problems.
Scientists bring a massive amount and breadth and depth of understanding on how animals might, not might not, need protected, far more than the average individual could possibly have. I think your inclination is the wrong way round. I would be inclined to start off believing them, and then check out their advice.
A view shared by every animal scientist I've ever met, the difference is that they also want to objectively support their understanding.
The list was potential "additional" risks to those everyday risks you list. We can't realistically control those every day risks, but we can question whether adding unnecessary risks is justified.
If this was some sort of legal case i.e. animal welfare lobbyists arguing that baiting should be made illegal, then my list provides the sorts of things that would need to be considered by the courts or parliament, which in turn would need evidence from objective scientific opinion.
I've no idea whether the things on my list represent low or high risks to birds, and this will inevitably depend on specific circumstance, but they are all "potential" risks that would need to be evaluated.
I think I've said my piece now, and if you think this is long, you should see the post I never finished