Advice on using Flash with birds please.

I am going to Florida from the UK next week and whilst there I am going to spend time in the Circle B Bar reserve which is a haven for birds and all kinds of Florida wildlife. I am taking my 600mm lens as I am keen to get shots of the Ospreys and, hopefully eagles fishing but don't anticipate using flash with this setup as I doubt the recycling times would keep up with the burst rate (but I am happy to be corrected). There is also an abundance of birds on the ground which I am keen to capture. I should make it clear that I am a keen but very novice bird photographer.
I have bought the Magmod (very similar to the better beamer) flash extender and would like some hints on using it please. The main question would be whether to use the flash on manual or TTL?
The flash is a Godox TT685 on a canon 1dx mkii the lens would be a canon 100-400 possibly with a 1.4 extender.
Can anyone offer advice or point me towards a source of information to help with this please.
I am not set on using flash so if the general advice is not to use it at all then I will take note of that, I just want to maximise my cahnces of getting good shots on this short trip.
Any advice is appreciated.

I played around with using a Better Beamer a number of years back with a 500/f4, with and without a 1.4 TC. While they do work to illuminate birds in very dark situations, I finally had to admit I did not like the predictable artificiality of the resulting light on my target. I often shoot in some dark conditions but have taken to honing my skills at reducing shutter speeds, opening the lens, and tolerating higher ISOs than I'd otherwise like rather than using a flash. Of course, it doesn't always work, but it works often enough that I'm satisfied with that route. Plus, it's just that much less gear to entangle yourself with while trying to photograph.

I would say to watch your metering mode so that you don't end up with bird silhouettes. Also, it is better to expose brightly with higher ISOs than to shoot at lower ISOs and try to bring your exposure up in post processing. That is it for any useful advice I can give.

If you do find yourself in a situation where you must us flash, you can greatly improve the Speedlite recycling time by using an external battery pack, such as the Canon CP E4.

https://www.bhphotovid​eo.com …Compact_Battery​_Pack.html

I have used this set up in the dark rainforest and it can keep up for low speed continuous shooting for birds up to 15 metres away in quite dark conditions. The results aren't always "pretty" as the lighting is quite flat with harsh shadows.

Here is an example showing no flash (left) then on camera flash (right) firing in ETTL HSS Mode to allow flash synch at 1/800 sec. The bird was some 15-20 metres away and 10-12 metres above ground.

Cheers

Dennis

I use flash a lot for birds and wildlife. I always use manual flash power control. I tried the Magmod but found it too heavy, none of my flashes can resist sagging due to it's weight.
So I stick with the Better Beamer. The Godox V860ii is really good due to Lithium battery, super fast recycle. Be aware that too many flashes in a row without a cool down time will melt the flash.
I know the Canon flash user manual gives you some guidelines, cool down times stated are minutes....

With the V860ii and better beamer I can get some fill flash well over 50m. (Half power will provide some fill at 50m)

In my opinion the first and third example here look natural and benefitted from flash.
The 2nd photo of the owls looks like flash was used: obvious catch light in the eyes which would be simple to remove in PP and the adult behind the Owlet has red eye, but I still prefer it.

Thanks everyone for your advice, I will give it a try next week. I have so much to get to grips with that I will not lose any sleep if it doesn't work first off. That is the benefit of digital over film, results are instant and at very little cost.

It's been on my "to do list" to learn how to better use my better beamer.

Usually the flash from my shotgun startles them, so I wouldn't recommend it.