Purple Martins and Hurricanes

[Laverne]

We went to the Sharpstown Roost again Friday night. We found the numbers were way down and the roost was again confined to the original 7 trees. There was still a considerable number of Purple Martins and they put on a spectacular show.

The bulk of the birds seemed divided into two segments and they came into the roost at separate times. I'm thinking we may have remnants of the old roost and a new congregation from a roost north of here that has migrated this far and was just stopping in for the night.

I wonder how long the migrants spend at each roost. I bet once they start their southerly march of true migration that they don't dawdle at any one roost for very long. Do you think there may be a "lead" bird that guides the HYs from roost to roost as they move to South America? Maybe an older ASY female who all the others are following? I know migration is instinctive, but how do these juvenile birds find an existing roost without the aid of one who has made this journey before? Maybe they really do just accidentally cross the path of local PMs and are lead to the roosts in this manner.

Whatever, I just wanted to let everybody know that most of the multitudes are gone. They have left in advance of the hurricane. I wonder how many birds are still at the Shreveport Roost? And what about the Lake Pontchartrain Bridge Roost? Has anybody been there in the past week?

[Donnie Hurdt MN]

This hurricane is not coming at a good time for the martin migration out of MS. and LA. I wonder if they instinctivly know to fly around such storms.

[abernathys]

Hey Laverne,

I have wondered the exact same things that you have. It would be great to know all those answers. I sure hope the PM's have some instinct about bad weather. I wish everyone in the path of Katrina the best of luck, my thoughts are with you. I just wonder what the numbers were for the PM's at Lake Pontchatrain Bridge within the last couple of days. Hope you have a good off season. Miss the PM's already.

Sandy

[Laverne]

Maybe the Purple Martins pick up on the decreasing barometric pressure. If not that, then the leading edge of gusty winds and bands of rain that arrive in advance of the storm might clue them in to the danger. Purple Martins can fly great distances very rapidly and with a tail wind from a hurricane pushing them - the majority of them should be safe. This is my hope.

My thoughts and prayers are with all the folks living in this storm's path. I hope they were able to get out of its way, too...

[Fred Kaluza~MI]

Laverne, we debated this last year as well and I'm sure it goes back way longer than that. I'm thinking that perhaps the birds INTEND to head out in synch with the arriving storms. In the northern hemisphere, winds circulate counterclockwise around a low pressure system. If the Martins time their departure properly, they can get very beneficial tailwinds if they stay to the west of the eye. Heading south, the initial winds would be tring to push them west "not bad" and then south. They need to be careful not to ride the winds too long because at some point the south tailwind begins to turn southeast and then east. Possibly this is what became of the vagrant Martins that were blown out into the open mid-Atlantic last season and turned up in theCanary Islands and Scotland.

[Laverne]

That's an interesting aspect. I'll bet you are correct. I can readily believe that migrating birds would use the weather to their benefit. I see birds rising on the thermals around our place all the time. I watch the PMs busily feeding beneath the leading edge of a summer thunderstorm and often see them feeding during a shower. The birds are very much at home in the air currents and a big ol' hurricane probably doesn't present much of a threat to them as long as it doesn't surprise them at night in the roost.

I was very concerned when I read about the PMs across the Atlantic. But, the fact they survived that trip says something - doesn't it? I wonder what became of those birds?

[Fred Kaluza~MI]

I hear that the Martins that made it across the Atlantic will probably live out their lives moving back and forth between Africa and Europe and will probably not find mates.

[Laverne]

Oh, how sad. Or they may find mates and develop into another non-native sub-species.

I wonder how many there are and if there might be some way to rescue them?

[Guest]

i thank that mother nature will take care of them. all animals have a way of knowing what the weather is going to do. I spend a lot fo time in the great out doors i travel to a lot of please to do big game photos. and beleve me when the weather is going to get bad . The animals know what is about to take place before we do . And they know just what to do . After all they have been here a lot longer then anyone of us has been hear on this earth . Iam sure they will be fine. every one have a great falll!! nathan - AKA (doe)

[Emil Pampell-Tx]

I agree with Doe, the animals know the weather. For example, on a large ranch in Montana, the cows regularlly bunch up before a blizzard, and they all go to a place behind a cliff where it was safer for them to stay. They did this moving about 1/2 day before the blizzard arrived. Smart cows or natural instinct?