Parks in NYC, traps or oases?

Last night saw the first of the Linnaean Society of New York's meetings for 2016, and they'd invited me and four other panelists to an hour's discussion on a topic close to my heart...

The topic? A favorite of urban birders confined to cities the world over; how do micro-parks and urban habitats impact on the ecology and stopover behavior of migrants?

Opening the evening, NYC activist and Bryant Park aficionado Gabriel Willow brought some provocative insights and anecdotes, (lots of which involved rare birds taking a rest on Corey's shoes) and some pretty cool mapping - visualising the scattergun distribution of green spots south of Central Park.

          L-R, Corey, Gabe, Eric, Heather, me

As Jacob Drucker dissected in this article (which precipitated last night's event), why do some of these spots concentrate birds and others not?  Do closely-spaced, small patches - think West Village or Hell's Kitchen, provide better stopover habitat than isolated big patches - like Bryant Park, which beckons like a false beacon under the neon towers of Midtown. Do manicured lawns with a continuous canopy of London planes work better than tumble-down community gardens, crammed with shrub diversity? What role do unseen green-roofs play?

This sapsucker stayed on my roof garden in Hell's Kitchen for over a week, 
drilling hundreds of sap wells into the small stand of 15 silver birches, which in turn attracted invertebrates, 
which attracted yellow-rumps, and so on....

It's a fascinating topic, and what became apparent over the evening, was that none of us panelists really knew. 

Migrants are opportunists, sure. They're flexible, behaviorally. You have to be if you weigh 12 grams and you're going to make it from the boreal forest to the beaches of Suriname. But why do some migrants turn up more than others? Why do some stay, and others leave? Does switching diet from arthropods to Starbucks muffin crumbs pack on the fat they'll metabolise through the thousands of miles of further flight to reach the wintering grounds? Or are they merely waiting to die? Questions that really deserve serious study.

While we were talking I was thinking of the investigations done by Daniel Janzen and others into minimum viable habitat size in Amazonia, and the effects of fragmentation on biodiversity in the forest. Here, cut one road, and some species will never cross it. The dynamism of NYC is the opposite of the stability of a rainforest, but the same techniques could be brought to bear to unlock and understand this dynamic system. 

Eric later reminded me of this proposal to turn Broadway into a bio-corridor, a long thin park stretching the length of Manhattan and cutting a sanctuary of sorts through its concrete heart...

This is a microcosm of the same corridor principle that is currently resurrecting the hope of wildlife in India, Brasil, Borneo. Corridors are normally last ditch efforts to stem fragmentation of unaltered habitats, a bas-relief left from the attrition of the land around. But what could a newly-minted corridor add to a landscape already at the limit of utility for most wildlife?

It seems to me that this most densely populated (and wealthiest) of places, sitting as it does on one of the world's critical migratory flyways, ought to be able to muster the motivation (and funding) to really study the problem and the possible solutions, a little bit more. 

Whether we end up reclaiming and rewilding Broadway, or just incentivize more green roofs, we'll make one of the world's most vibrant cities that bit more vibrant.

I have no idea what this leaning catbird was doing. 
Am pretty sure he was sunbathing, which I guess is what you do, in Bryant Park.  

Postscript: Here's what a Tokyo micropark looks like... Nano-park?

My photo
I work in NYC and own a wildlife and wilderness agency specializing in the southern cone of South America. I still do some guiding down there, especially looking for Fuegian and Patagonian avifauna. I'm particularly interested in the wintering ecology of neotropical migrants, and in avian biogeography in general. You can follow me at - @domhall And find me at - AventuraArgentina.com