Presidential candidate Sen. Elizabeth Warren (D-Mass.) has spent a total of $1.8 million on staff salaries and related fees — far more than her rivals. (Nati Harnik/AP)

With nearly 20 candidates running to become the Democratic presidential nominee, it can be hard to keep track of how each campaign is shaping up.

But first-quarter reports released this week provide an early look at how the candidates are spending their money, showing their priorities as they ramp up their efforts.

It’s still early in the primary season — the Iowa caucuses are in 10 months — and more Democrats are expected to announce their bid for the nomination.

Still, campaigns are already maneuvering to stand out from the crowded field, especially as they try to attract online donations and rise in the polls — both key metrics that will determine whether they can make it to the Democratic National Committee debate stage in June.

We dug through 16 Democratic campaign reports that were filed this week in first-quarter Federal Election Commission reports, which cover January through March 2019. Two more candidates announced their campaigns after March: Rep. Eric Swalwell of California and Rep. Tim Ryan of Ohio. We also reviewed President Trump’s report. Here are five takeaways:

1. Campaigns spent heavily to build their digital game.

A smart and expansive digital strategy is especially important in the primaries, as candidates work to distinguish themselves and capi­tal­ize on viral moments to raise money online.

Among the 16 Democratic campaigns reporting first-quarter spending, 12 spent a total of $6.7 million on online advertising and putting together their digital strategy, according to FEC filings. Other campaigns may have outsourced digital work to a vendor, which is not always reflected in FEC data.

The biggest spenders on digital ads from the first three months of the year were Sen. Bernie Sanders of Vermont ($1.6 million), former Texas congressman Beto O’Rourke ($1.3 million), Sen. Kamala D. Harris of California ($1.1 million) and Sen. Elizabeth Warren of Massachusetts ($905,000).

O’Rourke spent money at a faster pace on digital ads than the rest. Once he entered the race, he spent $75,161 per day on digital ads, accounting for 52 percent of his total spending for the quarter.

Sen. Amy Klobuchar (Minn.) spent $680,550 to build her list of supporters who receive her updates and fundraising appeals via email. Warren spent $68,500 on email list rentals and purchases. Other candidates who increased their email subscribers through a consulting firm did not report those payments in their FEC reports.

Campaigns spent $2 million on ads that ran in print, radio, television or — in the case of Rep. Tulsi Gabbard of Hawaii — billboards, and on consulting fees to develop their overall media and communications strategies.

2. Warren has hired a huge staff, compared with the rest of the Democratic field.

As the first major candidate out of the gate, Warren has scooped up campaign hires and amassed a staff of 161 in the first quarter. The senator from Massachusetts spent far more than her rivals on staff salaries and related fees — a total of $1.8 million.

Warren’s spending reflects her strategy to build an expansive ground operation, particularly in early states, which is especially important for her campaign to build and maintain momentum without the financial boost of large donors. Warren put herself at a fundraising disadvantage when she pledged not to hold fundraisers with donors who write bigger checks.

Her campaign said it now has 170 staffers, with about half working in states that vote early, such as Iowa and New Hampshire.

“Our team is building a grassroots movement and we need your help,” reads the campaign’s job posting for a staffer to manage 2020 staff hiring. “We will need organizers, communicators, writers, coders, wonks, and more.”

Warren spent considerably more than the other highest spenders on salaries and related fees: Sen. Kirsten Gillibrand of New York ($867,000) and Sanders ($830,000).

3. Pete Buttigieg spent less than $1 for every $10 he raised.

The mayor of South Bend, Ind., led the pack in posting a low “burn rate” — the pace at which candidates spend the money they raised.

Buttigieg, a newcomer to national politics, has benefited from his campaign’s media strategy to “get him out there everywhere” in media interviews, as described by his communications adviser Lis Smith.

The free media and social media buzz has helped raise Buttigieg’s profile. He revealed a big haul for a candidate who was relatively obscure when he jumped into the race: $7 million. Buttigieg had the fifth-largest fundraising haul for the quarter out of 16 candidates who filed their reports this week, while ranking 13th in the amount of money spent ($666,000).

On the flip side, Warren had a high burn rate, spending $5.3 million out of the $6 million she raised — more than 85 percent. Some Democratic strategists have expressed concern over her fast pace of spending, which is even more noteworthy, given Warren’s pledge not to hold fundraisers with donors who write bigger checks.

Despite a higher burn rate, Warren still has $11.2 million in her campaign fund, which includes the $10.4 million she transferred from her Senate campaign account. The extra cash transfer provides her — and other senators who have made the same decision — a cushion for their campaign spending.

4. Facebook is still a big source of spending by campaigns.

Despite the controversies surrounding Facebook after the 2016 campaign, Democrats are already pouring hundreds of thousands of dollars each into ads on Facebook.

Warren was the top Democratic spender on Facebook ads in the first quarter of 2019, spending about $617,000, according to Facebook Ad Archive data analyzed by Bully Pulpit Interactive, a campaign communications company.

Klobuchar ranked second, at roughly $547,000; Harris at about $522,000; and Sanders at about $521,000, the analysis shows.

President Trump was among the biggest political spenders on Facebook in the 2018 cycle, just behind O’Rourke’s failed 2018 Senate campaign.

In the first quarter of 2019, Trump continued to dominate Facebook advertising, spending about $3.8 million on ads through March 30, the data show. That gives Trump’s campaign the opportunity to improve its ability to target and persuade voters online while some Democratic candidates are still hiring digital staff.

5. Trump’s war chest is growing, despite spending at a faster clip than before.

Trump posted the best fundraising quarter of his reelection campaign in the first three months of 2019, raising $39 million between his campaign and two committees that raise money for his campaign and the Republican National Committee.

This quarter, Trump spent more money than he raised.

Of the $47.5 million spent by the Trump campaign, $1.7 million went to legal fees — a constant source of expenses for his reelection campaign. The legal fees stem from a variety of matters involving Trump’s 2016 campaign.

The president’s 2020 campaign continued to employ companies run by top aides in his orbit. The campaign spent $720,000 on Parscale Strategy, run by his campaign manager, Brad Parscale, and $50,000 to RS Consulting, run by Raj Shah, who until recently was deputy White House press secretary.

The Trump campaign’s expenses in the first quarter went to hiring staff and building up the campaign’s operations and long-term fundraising efforts, said Michael Glassner, the campaign’s chief operating officer.

Glassner said Parscale’s firm is a campaign vendor that provides digital, creative and strategic services, and that the campaign pays the firm fair market value. Parscale personally “does not receive a percentage of any advertising buys,” Glassner added. Shah’s company provided consulting services to help organize and set up the campaign’s communications team, he said.

Trump entered April with $49 million in cash, widening his financial head start over Democrats, who will be spending their cash to survive the primaries.