Sequential execution in node.js using arrays

I was learning sequential execution in node.js and came across an interesting problem.

Below is my code. Basically, I have 5 RSS Feeds in an array and I am trying to output titles of them sequentially. For this purpose, I have created an array of functions and utilizing this helper function from a book:

function next(err, result)
{
    if(err) throw new Error(err);

    var currentTask = tasks.shift();

    if(currentTask)
    {
        currentTask(result);
    }

}

Now, my program works correctly, If I prepare array as :

tasks = [

function(){handle(urls[0])},
function(){handle(urls[1])},
function(){handle(urls[2])},
function(){handle(urls[3])},
function(){handle(urls[4])}

];

However it outputs in random order and not sequential, if I prepare as:

tasks = [

handle(urls[0]),
handle(urls[1]),
handle(urls[2]),
handle(urls[3]),
handle(urls[3]),

];

What is the difference between above 2 arrays?

Full Code:

var request = require('request');
var parser = require('htmlparser');

var urls = ['http://psychcentral.com/blog/feed/rss2/', 'http://davidicuswong.wordpress.com/feed/', 'http://www.theglobalconversation.com/blog/?feed=rss2', 'http://happiness-project.com/feed', 'http://www.marriagemissions.com/feed/'];

function handle(url)
{
    request(url, function(error, response, body)
    {
        if (!error && response.statusCode == 200)
        {
            var handler = new parser.RssHandler();
            var rssParser = new parser.Parser(handler);

            rssParser.parseComplete(body);

            if (handler.dom.items.length)
            {
                var item = handler.dom.items.shift();
                console.log(item.title);
                console.log(item.link);
            }

           next(null, null);
        }


    });

}

function next(err, result)
{
    if(err) throw new Error(err);

    var currentTask = tasks.shift();

    if(currentTask)
    {
        currentTask(result);
    }

}


tasks = [

function(){handle(urls[0])},
function(){handle(urls[1])},
function(){handle(urls[2])},
function(){handle(urls[3])},
function(){handle(urls[4])}

];

next();