Peregrines & the Weather

[The Peregrine Chick]

Humans perspire, so we drink more fluids in the heat to replace what is lost.  Do Peregrines drink water, or do they get enough fluids from their meals?  

The birds cool off the same way we do, just alot less exposed skin to help out with the process.  However, they are smaller and therefore there is alot less mass to be hot.  The chicks get their water requirements from the food they eat.  Actually most of a peregrine's, adult or chick, requirements are fulfilled through the moisture in their food, but they do drink from water souces if the urge hits them, just not reliant on access to a water source for water as with many/most other bird species.  They also like to bath in the water, but it makes them vulnerable to predation, so not something one catches sight of often, I would assume that they would/could drink at that time too.  For those who noticed that when it rained, the chicks ran outside to flap their wings and "play" in the rain, that wasn't a response to the novelty of rainfall. 

[The Peregrine Chick]

How hot is too hot?  I've read fledgewatchers comment on chicks/fledgelings napping in the shade.  Does this mean that like us humans, the chicks tend not to be as active once the temps hit a certain point?
Does the humidity or humidex affect them?  Once the humidex hits 40c there are some segments of the human population that are at risk.  Is it the same for birds?

There doesn't seem to be an upper limit on that either when you consider that peregrines live on all the continents except Antartica (and some islands, Greenland & New Zealand most notably).  They get hot, move to the shade.  As for activity and chicks, nestbox-bound chicks are always napping, has more to do with the speed of their growth.  Chicks can overheat when they are young or if they are in a totally exposed location - one nest of Winnie's (female from U of M that nested in Omaha, Nebraska) was "overheated" one year due to nestbox position (it was corrected the same year).  As for fledglings, rules are the same as for the adults - hot, move into the shade preferably with a breeze, hotter still, find cool spot - concrete in the shade, metal in the shade to lie down on - cold against their breast/belly helps to lower body temps.

Humidity is as annoying for the birds as it is for them in terms of the mechanics of keeping cool.

[The Peregrine Chick]

How cold is too cold?  When do they start to migrate?

Two questions here ...

1) colder than you think - we had a female who overwintered here for close to 15 years, sat on the metal signs and everything winter and summer. There are birds now in the US who used to migrate, who aren't now.  The former resident pair in Columbus, Ohio are a good example of that.  I should note, that most peregrine subspecies, don't migrate long distances like ours, most move around in a local area, 100-200kms during the "off-season", still technically a migration, but not as we know it.

2) migration not based on temperature - based on when everyone (i.e. food) is moving it appears.  Warmer falls can mean more time up here, lousy spring weather can mean later returns.  Departure dates vary right into December from Winnipeg, returns are usually mid-Feb (earliest) to end of March, occasionally a resident bird will retun later than that, usually no later than mid-April.

[ShoeChick]

I've been reading some of the fledge watchers posts and have come up with some weather related questions.  I know that when very young, cold and wet weather can be fatal for chicks.  Once older, and the chicks can thermoregulate themselves, weather probably becomes less important.  however:

-  How cold is too cold?  When do they start to migrate?
-  How hot is too hot?  I've read fledgewatchers comment on chicks/fledgelings napping in the shade.  Does this mean that like us humans, the chicks tend not to be as active once the temps hit a certain point?
-  Does the humidity or humidex affect them?  Once the humidex hits 40c there are some segments of the human population that are at risk.  Is it the same for birds?
-  Humans perspire, so we drink more fluids in the heat to replace what is lost.  Do Peregrines drink water, or do they get enough fluids from their meals?